RAID Stripe, slice failure.

I have a RAID stripe set up on 3 disks, and I had a slice failure. Anybody know how I can remove the slice and recover the data on the other 2 disks?
Since OSX and all Unix-y OS's like to keep files contiguous, the loss should be minimal if i can only recover the data from the two remaining good drives - any suggestions?

I do have a backup, problem is, all the data I really need to recover is newer than my backup. 8-( Logically it ought to be recoverable -- because *nix file systems like to keep files contiguous, it stands to reason that the files themselves are contiguous on the two remaining good slices.
I understand and do not doubt that you speak from experience -- it's just that I understand a Windows file system being unable to recover said data - files being fragmented from one end to the other. But an *nix file system??? There is really no good reason why not.
None that I can think of anyway. It's not like Darwin fragments a file all over the place. 8-(

Similar Messages

Optimizing RAID: stripe/chunk size

I'm trying to figure out how to optimize the RAID chunk/stripe size for our Oracle 8i server. For example, let's say that we have:
- 4 drives in the RAID stripe set
- 16 KB Oracle block size
- MULTIBLOCK_READ_COUNT=16
Now the big question is what the optimal setting is for the chunk/stripe size. As far as I can see, we would have two alternatives:
- case 1: stripe size = 256 KB
- case 2: stripe size = 64 KB
In case 1, all i/o would be spread out over all 4 drives. In case 2, we'd be able to isolate a lot of i/o to separate drives, so that each drive serves different i/o calls. My guess is that case 1 would work better where there's a lot of random disk i/o.
Does anyone have any thoughts or experience to share on this topic?
Thanks,
Alex Algard
WhitePages.com
null

It does not matter. Do not mix soft-raid and hard-raid. One OS i/o operation can read from one disk and number of disk. Do not forget about track-to-track seek time.
Practice is the measure of truth :)
For example, http://www.fcenter.ru/fc-articles/Technical/20000918/hi-end.gif

FastTrak 376 RAID on KT4 Failure?

My System Specs.
MSI KT4 Ultra A6590VZ2 V1.3B1 121702
AMD Athlon(tm) XP 2200+
AMI BIOS 12/17/2002
PC2100 DDR Ram 3(512meg)
Radeon 9700 Video
Audigy 1 Sound
Sony DRU500a DVD-r-rw+r+rw (Primary Slave) IDE1
Maxtor 20 gig ATA/100 (Secondary Slave) IDE2
Maxtor 120 gig ATA/133 (Raid Master) IDE3
System fully operational for 6 months. Yesterday Morning BSOD from Windows XP Kernel_Inpage_Error. Power down machine, and power back up. Boot Failure. Seems as if the FastTrak RAID controller isn't reconizing my Maxtor 120gig ATA/133 Hard Disk. Reboot a few more times, same problem.
Download PowerMax from Maxtor's website to determine what hardware is failing. For me to run these diagnostics, I have to plug the Maxtor 120gig onto the normal IDE channels. The drive is reconized by the Primary IDE channel (interesting). If the drive is reconized by the standard IDE channels, why isn't the FastTrak controller reconizing it? I run diagnostic checks on hard drive. It seems to pass the tests.
Out of curiosity, I plug my Maxtor 20 gig into the RAID channel to see if it reconized it, it didn't. So this leads me to beleive that the RAID controller isn't functioning properly. I tried it in all Master/Slave jumper configurations as well.
I saw in Promise Technologies FAQ that it is possible to access the data from a standard IDE channel, with RAID 0 mapped drives. In this case, mine is RAID 0 with no array. Just 1 drive to the EIDE interface on the KT4 ultra board. Is this possible? How is it performed?
Any inquiries would be of significant help!
Thanks.
FastTrak 376 (tm) BIOS Version 1.00.0.18
Scanning IDE drives . . . . . .
No drive attached to FastTrak controller, The BIOS is not installed.

Quote
Originally posted by christop
All i can say is make sure the Jumpers on the HDD are set right for the way you have it set up
Well, jumpers shouldn't be an issue. This confuration has worked for six months. RAID 0, and Windows XP installation. Flawless and fast, even. , just yesterday morning, Kernel_inpage_Error BSOD, and now the FastTrak Controller won't reconize any drives. All HardDisks pass the manufactures diagnostics, plus, the drives work on the Primary/Secondary IDE channels.

RAID Stripe size for HD Capture

Hey everyone,
So I just captured a lot of Uncompressed 8 bit 4:2:2 1080i60.
The video alone requires ~ 118 MB/s sustained transfer speed for live capture without dropped frames.
I used our new MacPro. We built an internal RAID with 3 250 GB drives all striped together. I had to decide which stripe size to use. Since we have proportionally less files than the average RAID(200 or so at the most), and because our files are HUGE (2-40 GB), I figured a large stripe size would be apropriate. I set it to the max that Mac OS X software RAID supports, though I must confess I dont remember exactly what that was.
We had little trouble with capture, sustaining over 200 MB/s bandwidth with this setup according to the Blackmagic drive speed test. However, when the drives filled up, they (expectedly) slowed down quite a bit. I frequently did speed tests, and when it got low I had to switch into shooting DVCPRO HD to avoid dropped frames.
We had similar experiences before, when I had this same setup with the default stripe size, though it seemed overall a bit better with larger stripe sizes.
My questions are thus:
1) Is there any way to use a really large stripe (2MB or so) without buying a hardware RAID controller?
2) Is my thinking correct that if I have a small number of gigantic files I should use a large stripe size?
3) If I were to wipe out all my drives (including the 250 gig startup drive), and boot off the CD, could I tie all 4 drives together into RAID-0, and then install Mac OS X to that (and presumably partition it for a data storage volume)?
4) Does anyone know of a good 2-4 port eSata PCI Express card that has drivers for the MacPro? I know sonnet has a 2 port, but its one internal SATA and one eSata. I need at least 2 eSata ports for it to be worth my time, because I have a 4 drive eSata RAID box with 4 320GB drives in it. I can use the motherboard's additional 2 SATA connectors through a backplate SATA -> eSATA converter, and with 2 more eSATA ports through PCIe card, I would be able to use all 4 eSATA drives at once.
4 ports would be even better as I would like to leave internal ports for a BD-R or HD-DVD-R (or whatever they're called) drive later on.
Thanks!
-Derek Prestegard

1) Is there any way to use a really large stripe (2MB
or so) without buying a hardware RAID controller?
256k is the largest block size available with Disk Utility.
2) Is my thinking correct that if I have a small
number of gigantic files I should use a large stripe
size?
128k is the largest size I would ever think about using. I even use 32k in many situations. You can test it and see what works best for you. Large block sizes do not always translate into higher performance. I find more drives in the striped RAID set helps me more than larger block sizes.
3) If I were to wipe out all my drives (including the
250 gig startup drive), and boot off the CD, could I
tie all 4 drives together into RAID-0, and then
install Mac OS X to that (and presumably partition it
for a data storage volume)?
You could boot from a FW800 external and use all 4 internals
for a RAID but I think you will be happier with SATA host adapters.
4) Does anyone know of a good 2-4 port eSata PCI
Express card that has drivers for the MacPro
Here are a few options for SATA host adapters on a Mac Pro that I use. The WiebeTech Tera Card TCES0-2e SATA host adapter provides two SATA ports and works with the Mac Pro using SiI-3132 Mac drivers 1.1.6. You can see a review at amug.org:
http://www.amug.org/amug-web/html/amug/reviews/articles/wiebetech/tces0/
The FirmTek SeriTek/2SE2-E 2-port host adapter can be found here:
http://www.firmtek.com/seritek/seritek-2se2-e/
It works best on the Quad as it provides boot support and SMART drive support. On the Mac Pro you use the Firmtek cardbus 2SM2-E Mac driver until FirmTek can build new EFI drivers for the Mac Pro. No boot support is provided yet but it does pass SMART data to Mac OS X. Eventually the card will have Mac Pro boot support which will be nice.
Both cards use the SiI-3132 controller. If you mix the WiebeTech and the FirmTek cards the Silicon Image Mac driver version 1.1.6 will take over and block the SMART data info that the FirmTek card supplies. As this is the case, I would go with one brand or the other but not mix them in the same Mac Pro.
I have used three cards to provide six external SATA ports. You could use two cards with your external 4-bay enclosure. I would create a striped RAID with 4 external drives and two internal drives. This should provide you with the performance you need to handle 1080HD. If you want more power you could use 7 hard drives = 3 int. and 4 external.
Have fun!

Setting RAID stripe size?

Does anyone know how you can set the stripe size used for a RAID 5 setup? Even just knowing what the default stripe size used would be helpful.
I have searched in the forums and user manual but I have not found the ability to do this anywhere. Thanks in advance.

Don't use partition magic. You can't partition RAID. Cluster size of 128 is good. After making the Raid 0 array your bios will then have the option to boot from the array as if it were one HD instead of two. Install your OS. While windows is loading the driver data base you need to press f6 to load third party SCSI or RAID drivers. You should have a floppy with the drivers. After that your done. Make sure there are no boot partitions on the single drives before you configure the array, you might have problems installing Windows. At least that's been my experience.

RAID 5 Disk Failure

I have 4 1 TB HDs configured in a RAID 5 configuration in a Mac Pro. I just had one drive fail. I have replaced the drive and need to know if I need to format it using Disk Utility or will the RAID card automatically rebuild the drive or do I need to use raid utility and manually start a process. This is the first time that I have had to replace a drive. Any help would be greatly appreciated.
Thanks,
Mike

Hi
If an accident was to happen: eg: accidental deletion, dual drive failure, fire, water damage etc - regardless of what RAID configuration you had it won't prevent any data loss resulting from that accident. If you regard your data being absolutely necessary for the running of your business you should implement an effective backup strategy. At the very least a backup that can be taken offsite and be restored from if the worst was to happen.
Don't assume that everything is 100% safe. A RAID is not a backup. There is always a chance (albeit a slim one) it may fail.
Basically ask yourself one question. What value do I place on my data? Once you have the answer plan and budget everything else accordingly.
HTH?
Tony

Soft raid stripe from 3 different drives?

Hi,
I'm on a mac pro running 10.5.8. Apart from the boot drive I have two 150GB drives which I have as a stripe. I wanted to add to them a 250GB drive either whole or as a 150GB partition, but disk utility returned with a failure saying mixed partitioning not allowed.
Is there a possibility to create a stripe from these 3 combined to push up the performance a bit more?
Thanks
Tomasz

You would have to delete the existing array then create a new array using the three drives. Bear in mind that anything currently stored on the existing array will be lost so you need to make a backup of the array beforehand.

Can't read/access data - RAID 1 slice

I am trying to migrate from my old PowerMac G4 running OS X 10.4.11 to my new MacBook Pro running OS X 10.5.4 by reading a mirror RAID slice from my old Mac that is mounted in an external drive enclosure and connected by FireWire.
The problem is that the new Mac cannot read the old Mac disk, it never shows up on the desktop, or comes up as available when trying to use Migration Assistant. Then, if I go into Disk Utility, the external RAID slice shows up briefly with a locked yellow padlock beside it, then I suddenly get the window shade of death, and have to hold down the power button to reset/restart my MacBook.
Why can my new computer not read my old computers disk, and how can I change permissions, or make the old drive readable by the new mac.
Regrettably I am away from the original Desktop, and cannot load the old drive back into it, connect the two machines and migrate that way. My only option for reaching my necessary data is to retrieve it off the drive I have with me.
Thanks in advance for any help you can offer.

A bit of googling seems to suggest that a single drive from a mirror isn't directly readable - you need to "break" the mirror (while the array is still working), then each disk is readable as a normal drive.
Do you have both drives with you, or just one?
With just one drive, I guess that you would have to buy another drive and repair the mirror, like you would if one drive had failed. Not sure if that would work on a machine that didn't create the original mirror, though.

Raid controller show failure

Just noticed a red light on the front of the raid. now all lights are green again. but in raid admin
my lower controller status is red- Failure.
Does this mean that this controller is dead on need to be restarted?
Thanks for the help
Martin

Red light on RAID Controller means that your server does not have connectivity to your RAID Drives. If you are using fiber connectivity on your RAID, you can try connecting via ethernet by plugging your RAID to ethernet switch and plugging your server to same switch.If you have connectivity, that shows your problem is fiber.
Restart might fix the issue,but make sure you unmount RAID volumes before you do any restart.
If it does not work, you may try pulling out your raid drives and restart ,then push raid drives back in.
I hope it helps.
-IT Professional
Cosmont.com

Building RAID, hard drive failure?

I just reinstalled Arch to go with disk encryption and to setup my spare drives (4 2TiB HDDs) as one RAID5. Now, I started the process with
mdadm --create /dev/md0 --level=5 --raid-devices=4 /dev/sd{b,c,d,e}1
After about 11 hours, it was going at half the speed it started out at, and then eventually it failed saying that sdb1 was bad. I've now got this in /proc/mdstat:
Personalities : [raid6] [raid5] [raid4]
md127 : inactive sdd1[2] sdc1[1] sde1[4]
5860532931 blocks super 1.2
unused devices: <none>
So, two questions:
1) I've checked the drive with hdsentinel, and it says it is fine -- in fact, it get's a 100% in health, while two other drives in the array have less than that. Should I check it with something else as well? Should I just try to add it to the array? Should I get it replaced, just in case?
2) Whenever I have a drive I want to add to this array to complete it (I wanted RAID5 so I would need 4 2TiB drives to get 6TiB of space), how do I add it? I assume the process will be the same no matter if it's the same drive, just trying again, or a brand new one. I couldn't find anything on our wiki about it, and the information I'm finding about failures isn't really that understandable to me. Could someone point me to a good resource for this?
Thanks!

1) Run 'smartctl -t long' on all the disks, ideally when they're not in use/not mounted. It will tell you when it should be done, and you can also check 'smartctl -c' for percentage of completion. But it will take a while on large drives. Afterwards have a look at 'smartctl -A ... | grep Sector' and 'smartctl -l selftest' - there should be zero or close to zero reallocated/pending sectors and the self-test should be "completed without errors".
2) man mdadm

SLOOOOOWWW RAID Strip

Hello from Greece, My name is Akis.
I have a performance problem with my (OLD)k7tTurbo-R Mobo.
I have 2 (Brand NEW)maxtor MX-6L040J2 40gb 7200rpm HD's, and i've strip them with the integarated raid controler of the K7turbo-R.
The resault is nothing.... Benchmarks in windows Xp are showing me average sequential speed under 35MB/sec.According with tests in the internet i should have at least a rate of 50MB/sec +!!!!. Maxtor gives over 38MB/sec for this model of Hd!!!!
The Raid Controler is a Promise FastTrack 100.
The settings of the Raid is: For Desktop Use.
I use
Windows XP,
Mobo Bios 3.5,
Raid drivers 2.00.90 Build 10
The partition is formated with the NTFS system
Thanks everyone
PLZ HELP ME !!
Sorry about my english... I hope u've uderstand me

Hi,
try out this software approach :
http://www.msi.com.tw/program/service/forum/index.php?threadid=360&boardid=16&styleid=1
see if anything improves.

Raid Stripe size?

Is 512 kb a good size compared to the default 64?
Thanks
Lee

Quote
Originally posted by lugen
Hi,
I have the Modded bios I can change almost anything about it.
Lee
Can you? I am using the 5.4 modded bios and am unable to change the stripe size. If I go to anything different than the original Windows will not load.
Computer will just hang after the raid bios screen with a little blinking cursor at the top left.

Xserve RAID - Multiple drive failure.

Morning all,
An Xserve RAID I have been called to take a look at is behaving rather erratically! Here's the chain of events over the last 3 days:
(4 x 180GB - RAID 5)
- 2 folders (the largest in size) suddenly appear empty. The capacity and available space do not change.
- Some remaining files and folders appear corrupted / incomplete e.g. Quickbooks company file.
- Data Rescue appear to recover all data, missing files are recoverd as "orphaned" files.
- DRIVE 1 FAILS showing red light and disappearing from RAID admin.
- RAID set shows "degraded" but still accessible due to RAID 5 config.
- Replace drive 1 with 750GB Apple supplied drive.
- RAID 5 set rebuilds automatically showing green and "online"
- missing files in the 2 large folders still appears missing.
- DRIVE 2 FAILS
I believe the chances of 2 drives failing in such short succession are extremely small and I now thing that drive 1 is probably ok and that something else is at fault here.
Xserve RAID is on the latest FW 1.5.1 and no other errors are present.
Can anyone shed any light on this, could it possibly be the controller ?

The act of the rebuild could have been enough to push the second drive over the edge.
I would say... if the Xserve RAID has been running 24x7 since you purchased it, you may want to consider replacing it. The 180 GB drives were discontinued almost 5 years ago from what I recall... 5 years of constant use is really a long, long time for had drives. It's more typical in data center usage to replace drives after about 3 years of use (even if their MTBF is 500,000+ hours, those numbers are rather meaningless). Hard drives fail on a "bathtub curve," where once you get to the far end of it the odds of failure are great, and lots will fail around the same time. You can't rely on the Xserve RAID to run 24x7 for 10 years, or you'll definitely have problems. There is no RAID on the planet you can expect to run for 10 years without issues with the drives... even if you're using $1500 apiece fiber or SAS drives.

875P and Raid-0 Boot Failure - Rebuild Array?

Hi,
I was running combofix in safe mode when my computer suddenly blanked out and restarted. The 2 Western Digital WD1600JDs are set on the Promise PDC20378 controller and set for Raid-0 Striping. No noises or different temperatures seen, diagnostics recently checked out drives ok. One drive shows FREE the other assigned to ARRAY1. During POST it says Boot Failure. Can this be repaired? Is there a way to test if the Promise controller failed instead?
I have since installed a new WD3200AAKS on the ICH5 as a single drive with a new install of WinXP Pro. Curiously, I could not access bios for ICH5 with Ctrl-I or any other means. Maybe it was looking for 2 drives. I MUST restore or recover data from drives. Freeware recovery data has not been able to detect Promise drives.
What do fellas suggest?
Thanks!
James

My suspicion is that the drives are ok, that it's a software issue. I've just read about several people deleting the array but not destroying any data and then create a new array identical to the old one without initializing the discs. Have not seen it done with an MSI board, don't know if it would matter.

NAS200 RAID 1 - disk failure - how do i get to good disk?

it appears that the top drive of my NAS200 has failed
it was setup as RAID 1 mirror
i can't access the bottom drive
what do i have to do to get to my data?

You may need to connect the drives directly to a Linux PC. The drives are using a Linux- based file system so they won't be readable on a windows PC. If you don't have a Linux, you could try the DiskInternals Linux Reader. This will give you read only access to your files using windows explorer to view and select. You can also look into their data recovery software in case the files on your HD have been corrupted.

RAID Stripe, slice failure.

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