Toasters, We are looking at purchasing some new DS14 shelves with 72 GB disks. In order to properly forecast our disk space growth, I was wondering if anyone out there had taken a look at the difference between real and usable disk space realized with these new shelves and drives.
Basically, our environment is as follows: DS14 Shelf with 14 72 GB disks (1 RAID group of 8 disks, 1 RAID group of 6 disks), attached to a filer running DOT 6.1R1P1. We will have 1 spare disk and no snap reserve.
Geoff Hardin geoff.hardin@dalsemi.com
Geoff
We have a DS14 with 1 HotSpare, 1 RaidGroup @ 7 disks, 1 RaidGroup @ 6 disks, the default snapshot amount reserved, here is the df output:
/vol/vol3/ 551319184 107036 551212148 0% /vol/vol3/ /vol/vol3/.snapshot 137829796 398768 137431028 0% /vol/vol3/.snapshot
525 GByte available ;-)
Hope this helps --pwo
-- Peter W. Osel Sr. Network & Systems Manager Infineon Technologies Email: pwo@Infineon.COM North America Corp. Phone: +1 (408) 501 6321 1730 North First Street Fax: +1 (408) 501 2410 San Jose, CA 95112, USA WWW: http://pwo.de/
pgp key fingerprint = 79 2D DD 49 C0 AA D8 CF 2C F9 A5 6A BA 37 0E 28
73 GB disks "right sized" to 68000 MB (with zoned checksums.. anyone know if that's the same with block checksums?)
Since you can't use 14 disks and still have a spare, I'm doing this with one seven disk set and one six disk set.
(68000 MB * 7) - 68000 MB (parity) = 408000 (68000 MB * 6) - 68000 MB (parity) = 340000
408000 MB + 340000 MB = 748000 MB
748000 MB * 0.9 = 673200 MB (lose 10% to WAFL)
673200 MB * (1 GB / 1024 MB) = 657.42 GB
So... that would be 657.42 GB usable, assuming no snap reserve.
However, I think if you're buying a DS14 you'll get block checksum disks, which might be right sized to a different size, in which case it would be a different answer. :)
MD
----- Original Message ----- From: "Geoff Hardin" geoff.hardin@dalsemi.com To: "toasters" toasters@mathworks.com Sent: Thursday, December 13, 2001 12:35 PM Subject: Real vs Raw disk space
Toasters, We are looking at purchasing some new DS14 shelves with 72 GB disks. In order to properly forecast our disk space growth, I was wondering if anyone out there had taken a look at the difference between real and usable disk space realized with these new shelves and drives.
Basically, our environment is as follows: DS14 Shelf with 14 72 GB disks (1 RAID group of 8 disks, 1 RAID group of 6 disks), attached to a filer running DOT 6.1R1P1. We will have 1 spare disk and no snap reserve.
Geoff Hardin geoff.hardin@dalsemi.com
-
Geoff Hardin -
Peter W. Osel -
Tom Yergeau