got a 12 disk system - all 18gb 2 mirror for boot, now what to do with the rest? The storage is to be used for user space, web stuff and to store anything else (dump for data). I could do 5 mirrors, but thats a wasting quite a bit of space. Was thinking about raidz2, as its almost as reliable and better for space. Should i do 9 disk raidz2 with a spare, or could i do two raidz2 to get a bit of performance? Only done tests with striped mirrors which seems to give it a boost, so is it worth it with a raidz2 of this small size? Thanks for any help This message posted from opensolaris.org
On 3/23/07, John-Paul Drawneek <jpd at drawneek.demon.co.uk> wrote: I''ve got the same consideration at the moment. Should i do 9 disk raidz2 with a spare, or could i do two raidz2 to get a> bit of performance? > > Only done tests with striped mirrors which seems to give it a boost, so is > it worth it with a raidz2 of this small size?10 disks with two raidz2 pools leaves no room for a spare. You get 6 disks of storage and can lose any two disks before worrying. With Raid 10 you get 5 disks of storage and can loss anyone disk before worrying, but get better performance. I''ve thought about get the following: Raidz2 over 5 disks and Raid 10 over 4 disks with one spare. Use the mirror for small random read stuff, like maildir and use the raidz2 pool for iscsi system images. See also: http://www.solarisinternals.com/wiki/index.php/ZFS_Best_Practices_Guide#Should_I_Configure_a_RAID-Z.2C_RAID-Z2.2C_or_a_Mirrored_Storage_Pool.3F and http://blogs.sun.com/roch/date/20060531 - WHEN TO (AND NOT TO) USE RAID-Z and http://blogs.sun.com/relling/entry/zfs_raid_recommendations_space_performance Nicholas -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://mail.opensolaris.org/pipermail/zfs-discuss/attachments/20070323/3a9eec94/attachment.html>
I have read the links - good read So would i have two pools? Can i do to Raidz2 over 5 and a Raidz2 over 4 with a spare for them all? or two Raidz2 over 4 with 2 spare? Just trying to get the most storage out of it. But the setup you suggested sounds good This message posted from opensolaris.org
On 3/23/07, John-Paul Drawneek <jpd at drawneek.demon.co.uk> wrote:> Can i do to Raidz2 over 5 and a Raidz2 over 4 with a spare for them all? > or two Raidz2 over 4 with 2 spare?This is a question I was planning to ask as well. Does zfs allow a hot spare to be allocated to multiple pools or as a system hot spare. Or would this be done manually with a cron script. Nicholas -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://mail.opensolaris.org/pipermail/zfs-discuss/attachments/20070323/877290f7/attachment.html>
On Fri, Mar 23, 2007 at 12:11:38PM +1200, Nicholas Lee wrote:> On 3/23/07, John-Paul Drawneek <jpd at drawneek.demon.co.uk> wrote: > > >Can i do to Raidz2 over 5 and a Raidz2 over 4 with a spare for them all? > >or two Raidz2 over 4 with 2 spare? > > > This is a question I was planning to ask as well. > > Does zfs allow a hot spare to be allocated to multiple pools or as a system > hot spare. Or would this be done manually with a cron script. > > NicholasSpares can belong to multiple pools (they can only be actively spared in one pool, obviously). - Eric -- Eric Schrock, Solaris Kernel Development http://blogs.sun.com/eschrock
John-Paul Drawneek wrote:> got a 12 disk system - all 18gb > 2 mirror for boot, now what to do with the rest? > > The storage is to be used for user space, web stuff and to store anything else (dump for data). > > I could do 5 mirrors, but thats a wasting quite a bit of space. > > Was thinking about raidz2, as its almost as reliable and better for space. > > Should i do 9 disk raidz2 with a spare, or could i do two raidz2 to get a bit of performance? > > Only done tests with striped mirrors which seems to give it a boost, so is it worth it with a raidz2 of this small size? > > Thanks for any helpConsider that 18GByte disks are old and their failure rate will increase dramatically over the next few years. Do something to have redundancy. If raidz2 works for your workload, I''d go with that. BTW, I was just at Fry''s, new 500 GByte Seagate drives are $180. Prices for new disks tend to approach $150 (USD) after which they are replaced by larger drives and the inventory is price reduced until gone. A 2-new disk mirror will be more reliable than any reasonable combination of 5-year old disks. Food for thought. -- richard
> Consider that 18GByte disks are old and their failure > rate will > increase dramatically over the next few years.I guess thats why i am asking about raidz and mirrors, not just creating a huge stripe them> Do something to > have redundancy. If raidz2 works for your workload, > I''d go with that.Well i thinks so, the file system is currently on a raidz with three disk with no complains [b]Food for thought[/b] How do you fit sata into a scsi array???? [b]More food for thought[/b] So how do these two 500gb HDD work then? Do i just leave them on the side and the magic of ISCSI allows then to work and shared between boxes? Sorry for the gitty response but i am in the uk (see my details) so this 160 pound idea of yours is not 160 pounds. It is cost of the hdd plus the new box that can take them, so its a nice cheap option then :)> BTW, I was just at Fry''s, new 500 GByte Seagate > drives are $180. > Prices for new disks tend to approach $150 (USD) > after which they > are replaced by larger drives and the inventory is > price reduced > until gone. A 2-new disk mirror will be more reliable > than any > reasonable combination of 5-year old disks. Food for > thought. > -- richard > _____________________________________________ > zfs-discuss mailing list > zfs-discuss at opensolaris.org > http://mail.opensolaris.org/mailman/listinfo/zfs-discu > ss >This message posted from opensolaris.org
Just to clarify pool1 -> 5 disk raidz2 pool2 -> 4 disk raid 10 spare for both pools Is that correct? This message posted from opensolaris.org
I''d take your 10 data disks and make a single raidz2 stripe. You can sustain two disk failures before losing data, and presumably you''d replace the failed disks before that was likely to happen. If you''re very concerned about failures, I''d have a single 9-wide raidz2 stripe with a hot spare. Adam On Fri, Mar 23, 2007 at 01:44:06PM -0700, John-Paul Drawneek wrote:> Just to clarify > > pool1 -> 5 disk raidz2 > pool2 -> 4 disk raid 10 > > spare for both pools > > Is that correct? > > > This message posted from opensolaris.org > _______________________________________________ > zfs-discuss mailing list > zfs-discuss at opensolaris.org > http://mail.opensolaris.org/mailman/listinfo/zfs-discuss-- Adam Leventhal, Solaris Kernel Development http://blogs.sun.com/ahl