Single RAID 5 voume with partitions or mulitple RAID volumes?

I'm setting up in the RAID Utility. My question is: Is it better to create a single RAID 5 Volume and create 3 partitions using Disk Utility or create 3 RAID 5 Volumes from the RAID 5 Set? I want the OS, Data 1, and Data 2 to be separate and get the best performance possible. Any questions, let me know.

Hello, Techromancer27, and welcome to the AppleBoards,
Are you asking about the Xserve RAID the 14 drive hardware unit or setting up a RAID inside an Xserve using the RAID card? This discussion group is dedicated to the Xserve RAID hardware unit so it is easy for these questions to get confusing.
If you are asking about the Xserve itself and the internal disks you have only the option of creating a single RAID5. RAID5 requires a minimum of 3 drives which is all the Xserve can hold so your choice is pretty clear. If you are asking about an external unit of some kind with more drives you'll need to elaborate.
HTH,
=Tod

Similar Messages

RAID 5 re-partition

I'm running OSX 10.5.8 Server on a MacPro with RAID 5 running across 3 x 300 GB drives. The RAID was originally partitioned into 2 equal volumes; I now want to re-partition those volumes dynamically. Can anyone give me advice on how to do this?
Thanks!

You may not need commercial apps - Disk Utility can dynamically repartition drives, but there are some caveats.
The biggest question is how you created the partitions.
Did you create them at the hardware level (using raidutil)? or did you create one RAID 5 volume at the hardware level and use DiskUtil to partition it in two?
If the former then I think you're out of luck - raidutil can expand a volume, but not shrink it, so your only option is to delete one of the volumes, expand the other one, then create a new volume in the remaining space.
If you just created a single volume that you then soft-partitioned via Disk Utility, then you can resize the partitions if you used GUID as the partition format. The older APT can't be resized - at least that's what I recall... 10.5.8 is a little fuzzy now). If the disk is using GUID (and selecting it in Disk Utility will tell you) then you should be able to resize the partitions in the Partitions tab, otherwise it's a reformat and re-create job.

Partition recommendations under RAID 5 in Intel Xserve

So I am preparing for a new OS X server installation on an Xserve Intel with (3) 2 TB volumes to be setup in RAID 5. Our budget would not allow the addition of an SSD drive. I would like to have two volumes under RAID 5: (1) our boot volume with OS and (1) our data and sharepoints. It would be nice to keep the OS separate from my sharepoints in case I need to do a reformat and reinstall.
Our current server setup has a RAID 1 mirrored boot volume on a G5 with an XServe RAID 5 array (all one volume unpartitioned). I also have a second FireWire hard drive connected that I use to maintain a bootable clone of our boot volume.
On our new Xserve Intel with RAID 5, is there a way to have (2) partitions under RAID 5: (1) a 150 GB boot volume and (1) an approx 3.85 TB volume that will contain all of our sharepoints. Since our server is still in transit, I do not have a machine on hand I can experiment with.
Would you create two partitions on each hard drive then join each to their respective RAID 5 array so you have two volumes—one for the OS and one for the sharepoints?
Or, with RAID 5, would it be better to keep the array as one single volume and keep the OS and sharepoints all on the same volume without any partitions? My preference would be to keep it as stable a setup as possible? Obviously, if we were to keep the OS and sharepoints as one volume, I could image the OS installation once it is stable (and without the sharepoints) and keep the image on hand just in case I needed to revert to it in case of a problem.
What would you recommend?
Thanks!

Yes, you can partition the drives as you want. The only practical way to do this is to use hardware RAID to create the RAID 5 volume with all three disks, then use Disk Utility to split this array into two partitions.
You're not going to gain much benefit from this, though. The main advantages of using different volumes for OS vs. data is for performance reasons, but you lose that here since a) you're using RAID 5 and b) all your data is on the same physical disks anyway.
About the only thing you gain is a guard against the data volume growing to the point it consumes all space on the drives and hoses your OS (because the OS is on a different volume) or vice versa, but that's a small benefit IMHO.
As for disk failure, you're no better off with partitioning than you would be with a single partition for both data and OS - either way a single disk failure will be handled by the hardware RAID card until the disk is replaced, and all your data (both OS and Data) is equally protected/at risk either way.
So my recommendation would be to use RAID 5 across all disks and be done with. No further partitioning is necessary. It is, however, your server, and you can run it however you prefer
As for the stability issue - don't bother with a disk image - it'll be outdated before you blink and will be a PITA to keep up to date.
The easier option is to create a directory for all your sharepoints and just manage your backups such that this directory is excluded from your OS backups, and included in your data backups.

SSD Raid 0 With 2011 MBP

I have a late 2011 15" MBP with 2x Intel SSD x25-M 160gb drives (1 in the main bay, 1 in the optical bay). I chose these drives due to the limited bandwidth in the optical bay (it's restricted to 3g vs the main bays 6g).
I have found an issue that is rather curious when trying to install OSX onto the machine and it concerns the disk utility:
OS X Recovery Disk Assistant created with Mavericks will NOT see either SSD installed in either bay using the disk assistant (no format or parition possible of either drive. I can place the drives in external cases and they work flawlessly i.e. you can partition each drive but when you put the partitioned drives back in the MBP Mavericks will not see them).
OS X Recovery Disk Assistant created with Lion will see BOTH drives and will configure raid 0 successfully (once installed I ran the Mavericks install and it did not see the drive with Lion Installed on it so no upgrade was possible - I ran the internet download as well as trying to install Mavericks from an external firewire drive using a previous download of OSX 10.9).
I am about to try installing Mountain Lion to see if it will detect the SSD raid drive (it's downloading now). If that works I will try to then upgrade to Mavericks (doing this incrementally kinda *****).
I'm wondering if anyone else has ran into this problem? I have seen plenty of YouTube videos of people putting two SSDs in their MBPs and running Raid 0 with plenty of success. I'm just wondering if maybe there's a brick wall with anything other than a 13" MBP?
Thanks in advance.

Kappy - I think you missed part of the information in my last post:
I HAVE SUCCESSFULLY created and installed OSX (Snow Leopard, Lion, & Moutain Lion) using the Disk Utility provided by Apple to install fresh versions of each and they work perfectly.
I DID NOT clone these from external drives.
I would like to install Mavericks (I don't care at this point about the raid config but it would be nice) but the disk utility version of Mavericks (that you need to install that specific OS) will not see the SSDs installed inside the MBP. Even if I install Mountain Lion on a single drive and then try to upgrade to Mavericks the drives are not seen.
Even if i could clone the Mavericks install from an external drive onto the internal raid I still can't see either drive to even do it.

BIG PROBS with Creating RAID 0 with the Boot HD

Hey Everybody,
i have a Mac Pro with Mac OS X 10.5.3 and the folloring configuration:
1) a boot DH with 250GB
2) 2 x 500GB HD as a Raid 0 for Data
now i buy a new 250GB HD (then i have 2 x 250gb and 2 x 500 gb HDs) to create a nother RAID 0 with the boot HD... but that doesent work!
W H Y ? ? ?
i have look here in the forum fpr help, dont find a thread.
can some one help me? can i create a raid 0 with the boot hd? and when...how?
king regadrs..
christian

Lets say A and B are your 250gb drives with your current boot drive A. The two 500's are data drives C and D. My process would be to run Disk Repair on B, C and D. Then I'd run Disk Warrior on B C and D. Then boot from your DVD and run Disk Utility to repair A, just to ensure all is good. Then I would double check C and D to ensure they were duplicates, doing a Super Duper clone if needed. Then remove either C or D from your computer for safe keeping. Let's say you remove D. I would then wipe C clean and use SuperDuper to clone A to C and verify I have made a bootable perfect copy. You might even want to partition C into two drives and make two copies of A...just for temporary safety. After C has a boot copy, boot from C. Then you can use DiskUtility to create a simple RAID0 on A and B, and when that is done you can copy your C drive back into your A/B RAID. After booting from your RAID0 and then you can copy your data back from D to C (after reformatting C).
You cannot simply drag a drive from one to the other to copy it. It will not work as a boot drive doing that.
Keep in mind, if you do this, your A/B RAID has no backup. If you screw up an installation and hose it, you have nothing to fall back on. Time machine alone, or SuperDuper set to clone every day, or any of the commercial backup (or at least some of them) will give you more safety than a RAID0. RAID0 is great to save you from a single drive crashing, but more often than not the problem is installing some nasty piece of software that screws things up royally and RAID0 is wortheless for that. With your scenario, I'd buy another 250 so you can backup the RAID to that on a regular basis so if you totally screw up something you have a real bootable "last-known-good" image. After that get ANOTHER backup going to rotate off-site to save you from thieves and fires. At that point you can smile and know you really are reasonably safe. There are other ways to do this as others will explain. Several ways to skin this cat, but this is one option that will work.

Building a Raid-0 with two out of four internal drives?

Hello everyone
I have four drives in my MacPro:
1) OS+Apps
2) Virtualization
3) iTunes
4) empty
My iTunes library fills drive 3 and I am close to having a full drive.
I would like to 'span' my iTunes library over to drive 4 and was thinking about building a Raid-0 on drives 3) and 4).
Can I do this without any additonal software and hardware?
Do I simply do that in Disk Utility?
Can you foresee any limitations to that setup (except for fault tolerance)?
I assume performance is also sufficient as after all it is only for iTunes.
I am not worried about drive crashes as I can back-up the spanned drives externally
Any thoughts?
Thanks in advance

Quick follow-up information from the disk utility help menu:
"Using several disks as a single volume with a concatenated RAID set
If you need to set up two or more disks or volumes to work together as a single, large volume, you can create a concatenated RAID set. You can even increase the size of a concatenated disk set after it's been created by dragging more disks to it in Disk Utility. This RAID set is helpful if you have a file, such as a database, that's larger than any of the disks you have. Or you may need to create a mirrored or striped RAID set with one large disk and two smaller disks.
If you booted your computer from a disk that has multiple partitions, you cannot create a RAID set that contains partitions from your boot disk. To create a RAID disk that contains partitions from that disk, you must boot your computer from another disk or the Mac OS X Install disk first.
You cannot remove individual disks from a concatenated disk set."
So it seems I can add disks whenever I want but once added I can't remove them...

RAID mirror with software utility caused kernel panic every time

Using disc utility to make a mirror of 2 drives, click create and i get kernel panic and have to power off machine. if i try to start the machine with either of the two disks in it (together or individually) i get same kernel panic and have to power off.
The disks are in an external storage array (sonnet d500). I have a second storage array with raided disks in and i have raided disk inside the mac too. these all work fine..
originally 2 weeks ago i had the 2 disks working in a group of 4 disks set as a mirror of 2 striped disks. One disk in this setup failed and with this config you can never 'recover'or rebuild it - you get a degraded mirror and you can backup the data, but you must completely rebuild the raid again as the mirror of stripes never lets you add a new disk in again.period. not good.
I replaced the failed disk and rebuilt the mirror of stripes. this lasted a day until a second disk failed (all 4 were bought at same time so i was kind of expecting that to happen once one failed).
i replaced the second faulty hdd and thought about my disk usage and decided i would not make another mirror of stripes and i would make 2 mirrors instead for safe-ish storage and then transfer data to a striped raid set for editing from instead of direct from the mirror of stripes volume.
i tried to delete the raid but got a kernel panic
if i started the machine with any of the 4 disks i would get a kernel panic.
i moved the disks one by one into an older G5 running Tiger and managed to erase the raid info on 2 of them. The two new ones had some strange raid info and the Tiger machien thought there was an extra disk in the machine and would not erase or partition or allow me to destroy the raid whatever i tried.
I will be moving these now into an old XP PC to try to erase the boot records etc and erase them to be able to use them again in either mac pro or G5. painful..
so.. i ended up with 2 erased drives and have 2 new drives with dodgy raid info that causes kernel panics on the leopard machine and wont go in the Tiger machine.
The two erased drives are what ive now been trying to use in the mac pro to create a mirror - this now caused kernel panics when creating the mirror to start with and when installed in the machine at all. so i will be erasing them again in the tiger machine soon (its busy erasing with zeros another new disk that i added to the Tiger machine 2 weeks ago which seems to have some fault when raided!!! but thats another story).
so.. is anyone else having problems with creating basic mirror in 10.5.4 or is it just me??
i have a sonnet tempo e4p card with 2 external sata disk enclosures, latest firmware for the e4p card. all other previously existing raid volumes are working fine. i have one set of 2 striped disks, one set of 3 striped disks and one set of 2 stripes which are mirrored - all happy and working fine. but i cant make a new mirror of 2 disks...
I phoned Apple support and they said all raid info was kept on the disk itself and nothing on the actual machine and suggested i take the machine to an apple care centre for some tlc (although its disk i am having a problem with). since all my other disk arrays work fine i don't really want to rebuild the whole machine from scratch if i can avoid it.
Any suggestions of what i can try ??

well it turns out the new disk i bought just werent any good. my g5 powermac raid mirror issue was related to one new disk with lots of bad blocks (speed tools showed that up) so i have learnt my lesson on cheap non raid disks for raid..
am waiting on a couple of new ultrastar enterprise disks to tuen up so i can go back to the macpro and try to add a mirror again.
i am still stuck wih several new disks that i cannot format now in the macpro on leopard or on the g5 powermac with tiger.
ive tried softraid and that cant do it, speedtools pcformat util cant do it, disk utility crashes when i try to eras them and diskutil from termianl starts then doenst get anywhere and my pc sata card doesnt work so my last resort pc option still doesnt help me clear the partition map on these drives - ones that diskutility on leopard made for me - and drives which still cause kernel panics on the macpro if i put them in it..
here is what diskutil says on my g5:
/dev/disk0
#: type name size identifier
0: GUIDpartitionscheme *465.8 GB disk0
1: EFI 200.0 MB disk0s1
2: Apple_RAID 465.4 GB disk0s2
3: Apple_Boot 128.0 MB disk0s3
/dev/disk1
#: type name size identifier
0: Applepartitionscheme *233.8 GB disk1
1: Applepartitionmap 31.5 KB disk1s1
2: Apple_HFS Macintosh HD 233.6 GB disk1s3
/dev/disk2
#: type name size identifier
0: *465.4 GB disk2
/dev/disk3
#: type name size identifier
0: Applepartitionscheme *931.5 GB disk3
1: Applepartitionmap 31.5 KB disk3s1
2: Apple_HFS backup1T 931.4 GB disk3s3
/dev/disk4
#: type name size identifier
0: Applepartitionscheme *931.5 GB disk4
1: Applepartitionmap 31.5 KB disk4s1
2: Apple_HFS tempi 931.4 GB disk4s3
disk0 is the one with the bad partition info.
it thinks it has a double raid as the console shows on startup:
(both store45 and cache it thinks are on this disk - cache was my old mirror of stripes set on other machine, store45 was new name for my mirror, so seems like it hadnt deleted the original raid partition info before making new info which now kernel panics)
Jul 18 18:48:05 localhost kernel[0]: AppleRAID::degradeSet - starting the set "STORE45" (B9C48619-6B2C-4547-A01E-4864754EA7E2).
Jul 18 18:48:35 localhost kernel[0]: AppleRAID::degradeSet - starting the set "CACHE" (64F914A5-5556-4A44-AEE2-DC437868766B).
Jul 18 18:48:35 localhost kernel[0]: AppleRAID::completeRAIDRequest - error 0xe00002c2 detected for set "STORE45" (C0E139A4-2A6D-49C6-8F77-202AF7F9285D), member 50207BE5-E487-410E-8E8E-C4C4DCD2687B, set byte offset = 999527018496.
Jul 18 18:48:35 localhost kernel[0]: AppleRAID::completeRAIDRequest - error 0xe00002c2 detected for set "CACHE" (64F914A5-5556-4A44-AEE2-DC437868766B), member C0E139A4-2A6D-49C6-8F77-202AF7F9285D, set byte offset = 999527018496.
so currently i have 2 new 500gb disks which cant be partitioned back to anything at all on either machine. looks like i will have to buy a new pc to reformat them..
any suggestions of how to clear the partition map info and get them back to freespace ??

Software RAID setup by partition or by drive?

I've outgrown my ext FW drive that has served me well. May I still use it in a RAID 1 with a partition from a larger drive I am going to get?
I've spent the last few years backing up a TiBook to an ext FW 120GB Maxtor drive, which has worked well. I use SuperDuper to create the bootable backup every week or two and usually keep one or two old versions. It also holds my music and photo libraries, which are multi-GB.
With that said, I now have a MBP w/100GB int HD, so the 20GB partitions will no longer suffice. I've been thinking of getting a Maxtor 600GB RAID 0 as an upgrade. I like the speed but remain concerned about the risk of RAID 0. If SW RAID is by partition, it recently occurred to me that I can RAID 1 mirror the ext FW 120 GB drive and one 120 GB partition of the RAID 0 600GB dirve. Is that possible?
These appear to be the advantages: 1. RAID 1 on the backup, so if either the old drive fails or one of the drive in the RAID fails, the data is still fine. 2. Still get speed on the new RAID 0 ext. drive.
Please advise.
fellow

Hi fellow;
With the experience I have had supporting servers with RAID for IBM, I personally would try to find a different solution. I see too many variables, such as the buses and drives, to make me think it is going to be worth the effort. About the only RAID solution that were worthwhile were those that followed the rules.
Allan

Which is better, Raid 0 with two hdds or 1 ssd?

Hi,
I have a macbook pro Mid 2010 with two open hard drive bays (thanks to the mce optibay.) I was wondering if it would be better to put two caviar black hard drives in raid 0 on my macbook pro, or have one vertex 2 drive as a boot/applications drive and another data drive.
Thanks
Sam

I understood what the hard-drive-in-optibay meant. Regardless, it's still two platter-based hard drives versus an SSD. An SSD will be faster in your situation. If you had a lot of platter-drives in RAID0 and you had some sort of hardware based RAID controller with battery-backed cache, then maybe, possible, potentially, that (really expensive) platter-based RAID0 could be as fast as a SSD. You don't have that and can't put that in a notebook, so it ain't gonna happen for you.
Now add to the mix, the fact that RAID0 will lose data if any one of the drives in the array fails. You have two drives in RAID0 versus one drive in a non-RAID. The RAID is twice as likely to have a drive failure just because you have more drives. If you made the RAID from two SSD drives, which are more reliable than platter-based drives, then you're got something interesting. But you're still twice as likely to have a SSD-RAID0 array failure compared to a single non-RAID SSD. (And more than twice if it's platter-based drives in the RAID0 versus a single non-RAID SSD.) So it's up to you to determing how much risk you are willing to take...and how much you can afford.
Also note that some Macbook and Macbook Pro models have slower performance on the SATA port for the optical drive. (One assumes Apple tried to save a few dollars and put in a older, slower SATA controller for the optical drive.) I don't know exactly which models but if yours is one of those, then you may get uneven performance on your RAID0. Whether that is noticable or acceptable to you, will depend on a lot of things that you won't know until you try. (e.g.: model of drive, apps you're using.)
And it's good that "backup is easy for you." With RAID0 for the boot volume, you're that much more likely to have a failed boot volume. (IOW, can't boot the Mac at all, which means you'll be using that easily made backup a lot. ) Ideally, workstations that used RAID0 used them for the data, not for the OS. For example, in video editing, the scratch disk needs to be fast, but could be RAID0 because you "threw away" whatever was on the scratch disk after you were done editing, and presumably saved/copied the final edited product to another archival drive. But the OS was on a typical single drive non-RAID (or a RAID1 or RAID5 if necessary,) not on a single RAID0 array for both OS and data.
In your situation, you can't separate the OS and data onto separate RAID arrays, so in general, RAID0 is NOT what you want, regardless of whether you use SSDs or platter-based hard drives. But again, only you can determine how much risk and cost you're willing to gamble with.

Raid setup with g-tech raid

hello there.
bit confused by this raid business. Just got a 4tb g-tech raid system which has 2 drives of 2tb each.
It shows as one disk in finder. DO i only have to set 'RAID Type' to 'Mirrored RAID set' in disk utility? Do i need to make 2 partitions first?!
its just that it still shows 4tb available and i was presuming it would say 2tb?
any clarification welcome..! Dan

I don't know much about these, but since nobody who does has happened along . . .
There are different kinds of RAID. The two most common are:
A +Concatenated RAID Set+ (or RAID-0) combines multiple disks into one volume; the size is the total of all the disks in the set. It sounds like that's how yours is set up.
A +Mirrored RAID Set+ (often called RAID-1) keeps identical copies on each disk, so if one fails, you don't lose any data, and can keep running. The size is the size of the smallest disk in the set. It sounds like that's what you want.
If all the drives are in one enclosure, they're usually configured by hardware switches on the controller, or possibly software options you can set via an app that comes with the set.
Check with the maker (or instructions that came with the system) for setup information.

RAID Mirror using partitions

Hi all,
I've got 3 Samsung Spinpoint F1 1TB drives in my MacPro. One is dedicated entirely to Time Machine backup. The other two I would like to split into two equal partitions and then setup RAID (mirror) arrays using Disk Utility like this:
RAID 1 = Disk1,Partition1 + Disk2,Parition1
RAID 2 = Disk1,Partiton2 + Disk2,Partition2
The first RAID gets created without a hitch... but then the second RAID fails and won't create/mount.
Is this even possible on OS X 10.5.8? If so... I'd really appreciate any help, as it seems like this SHOULD work, but it just WON'T.
Thanks!
- John

Kappy,
Thanks for the additional info. I've got scads of backup going on... I regularly (like, hourly) use Chronosync to synchronize all of my important files between my Mac Pro and my MacBook Pro so there's one... I also user SuperDuper to maintain bootable backups on separate external drives for both computers... AND I've got two separate external backups of my important client files (backed up into a secure sparse disk image on two different external drives).
So... I came up with the scheme of having the RAID on the boot disk while I was trying to re-allocate some new drives from my MacPro and external drive enclosures. I realized that the original, 320GB drive that came in the MacPro was a dog and was significantly hampering performance (the MacBook Pro is actually faster at performing disk-related tasks!). So... I had a Samsung SpinPoint F1 1TB drive that I was planning to put into an OWC FW800/400/USB2.0/eSATA drive enclosure to use as part of my external backup scheme that I thought would serve me better as my boot disk. But, since I've only got about 200GB of the 320GB filled on the current drive, I figured I had a lot of space on the 1TB drive that would go to waste.
Hence... I hatched the "brilliant scheme" of partitioning 2 of the 1TB drives in the MacPro equally and then creating a RAID... figuring that would provide at least some reason for having the overly-large drive for my boot disk. RAID mirroring would give me a level of protection against disk failure and would reduce the "clutter" of having too many drives/partitions showing up on the desktop and in Finder.
But... all of your comments are excellent ones. So, I'm sticking with the interim solution I posted earlier. No RAID on the boot disk partition, but a RAID on the important client files partition to provide drive-failure protection above-and-beyond my existing backup schemes.
Thanks, again, for all of your input.
Regards,
- John

Raid 0 With Internal And External Different Size Drives??

So I want to setup a raid 0 with my computer setup but have some questions.
I have 3 external drives, 500GB, 2TB, and 1TB.
Can I partition the 2TB and 1TB and use the 500GB partition I make on each drive for the raid, so all 3 are 500GB?
Can I also partiton my 1TB internal hard drive in half and use the new partition in the Raid?
Am I going about the best way to set this up or will this not even work in the first place?
Thanks for any info and helping!!

So basically I setup my iMacs drive and my external 1TB drive as a raid 1 and it will write the data to both drives at the same time right?
Correct.
Will this slow anything down at all?
Yes.
I gave up on TM myself.
Get carbon copy cloner to make an exact copy of your old HD to the New one...
http://www.bombich.com/software/ccc.html
Or SuperDuper...
http://www.shirt-pocket.com/SuperDuper/
Or the most expensive one & my favorite, Tri-Backup...
http://www.tri-edre.com/english/tribackup.html

Problem Rebuilding RAID set with 10.5?

I have 1 RAID set (mirrored with autorebuild) composed of 2 (identical) HD. I got a message in 10.5 Disk Utility that one disk had failed and that the set was degraded.
I replaced the drive and I am getting an error message during the rebuild "Unrecognized filesystem".
I can still see and access my RAID set (1 slice still ok) so minimal damage here but I don't understand why I am getting this error message when trying to rebuild.
Any idea?
Thanks
setup:
-mirrored raid set
- autorebuild selected
- 2 slices (160Gb, GUI, OS journaled ext)

Hi VK2CPJ,
Today ( I slept on this idea was exhausted from previous day) tried on two blank eide drives in a raid box, no raid built just two independent drives, one set for master the other slave. A couple of observations:
I did not raid because I want one small partition to contain a Leopard boot install from the DVD. The message I received from disk utility was that if I restore that DVD my raid may be unusable(if I did raid). So I did not raid the drives but let them stand as master and slave. I wanted to do a APM on the small "boot" partition to see if my intel and PPC Mac would in fact boot from that restored Leopard DVD boot partition. I used start up pane on both PPC and intel and they would not boot up from that Leopard partition even though the start up pane showed the disk as a startup device. Using the option key booted both Macs. Now I'm not sure if doing this was to procedure because the Apple docs says to use a PPC Mac to do this process. Which I have a difficult time to understand. I'm assuming that the doc says that because APM would be default and assisting the user not to make any option mistake. So currently I'm trying this same procedure using a PPC Mac to test out whether start up pane will boot both Macs. I don't think it will but do think using option within the start up manager will work. If so then does this mean imply that the start up pane has a bug or that user does not require a PPC Mac to do the setup process. Let you know shortly.

RAID-5 over RAID-1, with encryption

I'm planning to restructure my fileserver. It has (well, will have) 8 hard drives for data, each 1.5 TB in size. I want to create 4 mirrored pairs, and then place each pair in a RAID-5 array, for a total usable space of 4.5 TB. I want to place encryption on top of it, with dm-crypt/LUKS, with either ext4 or xfs on top of that (_probably_ ext4, but it's easy to change that after I have the block devices set up).
I guess my questions are mostly about performance and best practices.
For reference, the server has 6 GB RAM (although I can easily buy more if needed), and a first-gen i3 (which, sadly, does not have hardware AES support). The hard drives are all running off the motherboard's SATA ports, but I can buy (and probably will buy at some point) a good JBOD controller.
I should also say that the server will be used for (a) keeping differential backups of my other computers (probably only 500-750 GB in backup files), (b) streaming music / HD video, (c) torrenting. So the usage is really a fix of access patterns, but the files should generally be larger-than-average (most files will probably be over 10 MB), and there will probably be many files open at once.
1) What kind of chunk size should I use? I assume using equal chunk sizes for the mirrors and the RAID-5 array would be good. I was thinking 256 KB (which would yield a 768 KB block size in the FS), but that may be a bit big.
2) I hear it's best to put the encryption between the filesystem and the top-level block device (which is the RAID-5 array in this case). The other feasible option is placing it directly on the drives (well, on the drives' partitions). Is this true?
3) An alternative configuration would be to mirror two RAID-5 arrays together, but partial rebuilds would take longer and put more stress on the drives. It would be nice to get some confirmation that I'm right in my reasoning here, and that RAID-5 over RAID-1 would be better than RAID-1 over RAID-5.
Any other advice with such a setup is welcome.
Thanks for your input!
(Note: This was brought about due to the failure of a few hard drives in my fileserver. To that end, I am unable to really test anything with all the disks until I get them back from the RMA. I can still play around with a few disks for now, though.)

alphaniner wrote:α. BAARF
Yeah, someone linked me to that too. I looked through their reasoning (well, about 3-4 of the links on that site) and I don't think it really pertains to me, because:
During a full rebuild (of the overarching RAID-5 array), one (or even up to three) more hard drive failures will not cause issues.
RAID-6 provided ample performance for me, so I assume RAID-5 will be the same (if not better).
Adding more hard drives would entail (a) a new controller, (b) a new case (probably a server chassis, to handle 10+ hard drives), and possibly (c) a new PSU. So it's actually not at all cheap for me to buy them.
The reason I'm thinking of RAID-15 and not RAID-51 is because if 1 drive fails, the rebuild only reads from one drive (to restore that mirror). If 1 drive fails in RAID-51, then the rebuild must read from the other 3 drives. The situation can easily get worse with 2 failures, since this would cause reading from probably 2 but at most 3 drives in RAID-15, but would cause reading from all 6 with RAID-51. Basically, recovering from a failure would take about 3 times as long, which means about 3 times the stress on the remaining drives while the array is more vulnerable.

Installing Maverick on a MacPro with OS 10.7.5 and using RAID 1 with 2 * 1TB disks. 50% used.

I have a MacPro with 2* 1TB disks running Mac OS 10.7.5 using a RAID card running RAID 1. 50% space used.
How can I install Maverick safely (i have a Time Machine Backup). The install will not use the RAID set as a boot volume.
Reading the RAID manual there is discribed a way to create a bootabkle partition and RAID 5. But it starts out as a newly purchased configuration.
I have a used configuration. I would like to reuse the data.
Is there an installation section for my type of configuration?
THKS for all help.
Regards
Reint

I have found the answer myself already.
1.     Take a full backup on a medium which also will restore.
2.     Start your system with original start-up DVD.
3.     Start RAID pgm. Dissolve your current RAID set.
4.     Create a new RAID set with a logical volume on it.
5.     Restore from your backup your current system.
6.     Install Maverick on this system.

Single RAID 5 voume with partitions or mulitple RAID volumes?

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