Marge...
I'd much rather have RAID-DP than RAID5 - RAID-DP affords for faster read\write access and the ability to lose TWO drives without losing data (raid5 can only lose one).
If you feel strongly about not wanting to use multiple disks for parity, use traditional RAID4 - still faster read\write access when compared to RAID5, but obviously you won't have as much resiliency to failure.
That will surely boost your usable space as well.
Glenn
-----Original Message----- From: owner-toasters@mathworks.com [mailto:owner-toasters@mathworks.com] On Behalf Of margesimpson@hushmail.com Sent: Sunday, July 30, 2006 8:19 PM To: toasters@mathworks.com Subject: RE: Storage space overheads!
Hi all, Thank you very much. It seems out of 100GB, what usable space I can have is 55GB (55%). I feel yauk! But it seems at this point of time, its the only solution. I wish NetApp had Raid5, this could have eliminated some issues like using 2 dual-parity drives. Thank you again for your responses about SATA and FC disks.
Cheers, Marge.
On Fri, 28 Jul 2006 19:19:08 +1000 "Holland, William L" HollandWL@state.gov wrote:
We have a R200 which has 168 ATA drives. I expected a high failure rate on these as ATA drives are not rated for continuous duty. I have been surprised, and pleased, that failure rate has been very low - perhaps 3 drives in a year. Not sure about the SATA. The way I am moving is to use (S)ATA for my NAS (user shares) and FC drives for hosting my iSCSI LUNs. Databases need the higher performance of FC, simple file shares do not.
-----Original Message----- From: owner-toasters@mathworks.com [mailto:owner- toasters@mathworks.com] On Behalf Of margesimpson@hushmail.com Sent: Thursday, July 27, 2006 10:00 PM To: toasters@mathworks.com Subject: RE: Storage space overheads!
Hi Glenn D, Glenn W, Andrew, Michael, Holland and Holland, Thank you all for your feeback.
To summarize, the following is true (i.e., about storage sacrifice):
- Disk are right sized (realigning size in blocks from different
vendors...eg., for 72GB we get 68GB) before using by NetApp.
- dual parity (2 disks on RG of 16 => 14D+2P)
- spare disk/s
- WAFL & RAID overhead (~ 5%).
- aggr reserve 5% default
- vol snapshot reserve 20% default
- for LUNs: 50% for base snapshot + extra space 20% of remaining
data space
- user data should always be below 90% to avoid performance
bottleneck and defrag issues.
That's sounds bad to me, but if you all feel to be true then its must be a solution.
How about putting SATA disks on the primary filers to save costs? Whats are the problems in replacing FC disks with SATA? Whats record about SATA disks, I heard they are terrible? (Failure
rates is abnormal)
Thanks again for feedback. Marge.
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