Raid 0 (Stripe) for OS X boot disk? Best Performance and block size

Question

Hi,
so this is a new thread to an older question I had and would like some feedback on;
I have a new Mac Pro with 4 matched 1TB caviar black drives. I WILL be doing Full Time-Machine Backups, as well as an independant full-system backup regularly.
That being said, I have 4 drives open and am looking for suggestions. I am leaning toward 2 sets or stripes (one for the OS and one for 'work space', the former with a 32k stripe block size, the latter with 64k (will hold video, audio, scratch, and, yes, Games).
Does this sound alright? Is there an issue with Striping the boot drive? Is the block size or 32 (or 64) optimal?
Thanks!
Dan

Answer 1

Hi D# Shooter, regarding your question,
D3 Shooter wrote:
You brought to mind something I did not take into consideration, Time Machine. I really like the simplicity of TM as it saved me once before. So, could you tell me, for photo files, some video, how much does the striping (% wise) improve the accessing and filing of such files compared to no striping but, using internal drives (7200/WD/1TB/Caviar)? I have not done striping before and want to weigh in because of the back up storage issues now. Thanks.
J_ust give it a try and see if it is worth it for you_.
Striping:
• just enhances (reduces the access/transfer) because in practice the access is distributed in parallel across several DDM's (Old school but it works great!). I think for video and file work the advantage is that you can access the whole object sooner (rather than faster).
• this distribuition also reduces a load of old style queing on the device ove rthe path. THis was resolved in the late 1980's so no reall rocket science here.
the issues with striping are few and basically over all the raid implementations (except JBOD which of course is not raid) when compared to a single spindle. The discussions are enormous and plentiful via google and experiences and opinions vary widely.
Fir the I.T. peole its the advantage they get for access using a smart disk controller that caches goosies like indexes and stuff so that they can sustain a zillion trivial transactions/sec (i.e. banking & internet stuff).. stuff that is of no interest to me
For the creative people and many applications that are BLOB's (like video, film and remote sensing objects) getting use of the objects sooner (not faster) is of prime importance for workflow efficiencies. If you have this need then striping stiff across disks is for you!
TIMEMACHINE.app works fine as it seems fairly agnostic to whats implemented under the disk file system. MY issue with time machine is that I don't want it looking after my production stuff, only to keep an eye on my admin I.T. type stuff such as ~/ and data data files.
As posted on ths thread:
• availability is the major concern with any file system (cloud or raid or other). RAID with parity schemes and double parity schemes (Raid1,,3,5,6) and implementations such as RAID6+ LSF (log structured file) are all wonderful for this business workflows that need it.
• timely access in a workflow is another
• cost benefits are another
However a *great benefit* for me of *consolidating small storage components under one huge file system is that you dont have to COPY any thing around*. THis is marvelous especially when you think you have to move 2TB's of stuff from one place to anther. THis a takes a lot of time with elcheapo didks that dont have fast interfaces such as SATA/SAS of FC for example.
As always and has been addressed by others on this thread (Hatter) if you lose a component storage device the whole file system is hosed or severely degraded unless you spend a lot of money on full ranks of DDMs with hot spares and a very good RAID controller card. Again its money.
YEah sure you can carry some PARITY RAID implementation around across 3 didks but the storage capacity usage is dreadful. THis is why more complex RAID implemntatiosn are in groups of 10+ dDMs.. (yep poepl can argue.. but this is the mainstream).
My external disk arrays are merely two LUNs (SAS DOMAINSA) that have two file systems implemented using 2 x 4TB 1TBs DDMS - all RAID0 - no parity (no availability) - I just want speed. I look after my own "availability" withm= my archive solution. If the operation dies, I stat again. I'm happy wi that. RAID 5 has write penalty performace hits (well known +update in place+), , RAID 6+ is lousy for huge objects but good for I.T. but ok if you lose two disks in a stripe (RANK).
They all have their flaws... and mirroring a RAID0 (RAID1/0) seems to be popular with storage vendors because they can see you more disk and thats proper business workflow depends on it.
However you can achieve this stuff if you change your workflow slightly.
Other than these the rest is tech specs and stuff under the cover.
So you what is right for you and your business.
I dont like spending money on nasty elcheapo FW800 LeCIE disk enclosures with the their junky components and their ilk having been done badly on several corrupted devices and lsing TB;s of content - this is why I invested in a high speed LTO4 ULtrium data tape archive solution.
sorry for long post..
w