Hello, 1) If i create a raidz2 pool on some disks, start to use it, then the disks'' controllers change. What will happen to my zpool? Will it be lost or is there some disk tagging which allows zfs to recognise the disks? 2) if i create a raidz2 on 3 HDs, do i have any resilience? If any one of those drives fails, do i loose everything? I''ve got one such pool and i''m afraid it''s a ticking time bomb. Thanks -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://mail.opensolaris.org/pipermail/zfs-discuss/attachments/20080221/7dd3169d/attachment.html> -------------- next part -------------- A non-text attachment was scrubbed... Name: smime.p7s Type: application/x-pkcs7-signature Size: 3361 bytes Desc: not available URL: <http://mail.opensolaris.org/pipermail/zfs-discuss/attachments/20080221/7dd3169d/attachment.bin>
On Thu, 21 Feb 2008 11:58:55 +0100 Justin Vassallo <justin.vassallo at entropay.com> wrote:> 1) If i create a raidz2 pool on some disks, start to use it, then the > disks'' controllers change. What will happen to my zpool? Will it be > lost or is there some disk tagging which allows zfs to recognise the > disks?Hi Justin, ZFS makes use of Device IDs (aka "devids") which are unique to each device, and persistent. Changing the controller should not change the devid. You can examine devids using "prtpicl -v" and searching for the word "devid"> 2) if i create a raidz2 on 3 HDs, do i have any resilience? If any > one of those drives fails, do i loose everything? I''ve got one such > pool and i''m afraid it''s a ticking time bomb.I don''t think you''ve got enough disks there, I believe you need another one. Have a look at the ZFS doco (docs.sun.com) and the ZFS Best Practices Guide (www.solarisinternals.com and www.genunix.org). James C. McPherson -- Senior Kernel Software Engineer, Solaris Sun Microsystems http://blogs.sun.com/jmcp http://www.jmcp.homeunix.com/blog
> 1) If i create a raidz2 pool on some disks, start to use it, then the disks'' > controllers change. What will happen to my zpool? Will it be lost or is > there some disk tagging which allows zfs to recognise the disks?It''ll be fine. ZFS opens by path, but then checks both the devid and the on-disk vdev label, which is dispositive when the others disagree.> 2) if i create a raidz2 on 3 HDs, do i have any resilience? If any one of > those drives fails, do i loose everything? I''ve got one such pool and i''m > afraid it''s a ticking time bomb.You''re fine. RAID-Z2 is N+2, and you have N=1. A three-way mirror would give you better performance (because there''s no parity to generate), but from a resilience standpoint they''re equivalent. Jeff
On 21 February, 2008 - Justin Vassallo sent me these 10K bytes:> Hello, > > > > 1) If i create a raidz2 pool on some disks, start to use it, then the disks'' > controllers change. What will happen to my zpool? Will it be lost or is > there some disk tagging which allows zfs to recognise the disks?It should find stuff.. export/import..> 2) if i create a raidz2 on 3 HDs, do i have any resilience? If any one of > those drives fails, do i loose everything? I''ve got one such pool and i''m > afraid it''s a ticking time bomb.3-disk raidz2 is like a 3-way mirror, but less efficient.. You can lose 2 disks without data loss.. /Tomas -- Tomas ?gren, stric at acc.umu.se, http://www.acc.umu.se/~stric/ |- Student at Computing Science, University of Ume? `- Sysadmin at {cs,acc}.umu.se