Re: [zfs-discuss] one ZIL SLOG per zpool?

2010-08-13 Thread Edward Ned Harvey
From: zfs-discuss-boun...@opensolaris.org [mailto:zfs-discuss- boun...@opensolaris.org] On Behalf Of Chris Twa My plan now is to buy the ssd's and do extensive testing. I want to focus my performance efforts on two zpools (7x146GB 15K U320 + 7x73GB 10k U320). I'd really like two ssd's for

Re: [zfs-discuss] one ZIL SLOG per zpool?

2010-08-13 Thread David Magda
On Fri, August 13, 2010 07:52, Edward Ned Harvey wrote: If you have ZIL disabled, then sync=async. Up to 30sec of all writes are lost. Period. But there is no corruption or data written out-of-order. The end result is as-if you halted the server suddenly, flushed all the buffers to disk,

[zfs-discuss] one ZIL SLOG per zpool?

2010-08-12 Thread Chris Twa
I have three zpools on a server and want to add a mirrored pair of ssd's for the ZIL. Can the same pair of SSDs be used for the ZIL of all three zpools or is it one ZIL SLOG device per zpool? -- This message posted from opensolaris.org ___

Re: [zfs-discuss] one ZIL SLOG per zpool?

2010-08-12 Thread Darren J Moffat
On 12/08/2010 07:27, Chris Twa wrote: I have three zpools on a server and want to add a mirrored pair of ssd's for the ZIL. Can the same pair of SSDs be used for the ZIL of all three zpools or is it one ZIL SLOG device per zpool? Only if you partition it up and give slices to the pools,

Re: [zfs-discuss] one ZIL SLOG per zpool?

2010-08-12 Thread Edward Ned Harvey
From: zfs-discuss-boun...@opensolaris.org [mailto:zfs-discuss- boun...@opensolaris.org] On Behalf Of Chris Twa I have three zpools on a server and want to add a mirrored pair of ssd's for the ZIL. Can the same pair of SSDs be used for the ZIL of all three zpools or is it one ZIL SLOG

Re: [zfs-discuss] one ZIL SLOG per zpool?

2010-08-12 Thread Roy Sigurd Karlsbakk
People are always tempted to put more than one log onto a SSD because Hey, the system could never use more than 8G, but I've got a 32G drive! What a waste of money! Which has some truth in it. But the line of thought you should have is Hey, the system will do its best to max out the

Re: [zfs-discuss] one ZIL SLOG per zpool?

2010-08-12 Thread Chris Twa
Thank you everyone for your answers. Cost is a factor, but the main obstacle is that the chassis will only support four SSDs (and that's with using the spare 5.25 bay for a 4x2.5 hotswap bay). My plan now is to buy the ssd's and do extensive testing. I want to focus my performance efforts