If 2 disks of a mirror fail do the pool will be faulted ?
NAME STATE READ WRITE CKSUM
homez ONLINE 0 0 0
mirror ONLINE 0 0 0
c0t2d0 ONLINE 0 0 0
c0t3d0 ONLINE 0 0 0
mirror ONLINE 0 0 0
c0t4d0 ONLINE 0 0 0
c0t5d0 ONLINE 0 0 0
mirror ONLINE 0 0 0
c0t6d0 ONLINE 0 0 0
c0t7d0 ONLINE 0 0 0
Thanks.
--
Francois
Francois wrote:> If 2 disks of a mirror fail do the pool will be faulted ? > > NAME STATE READ WRITE CKSUM > homez ONLINE 0 0 0 > mirror ONLINE 0 0 0 > c0t2d0 ONLINE 0 0 0 > c0t3d0 ONLINE 0 0 0 > mirror ONLINE 0 0 0 > c0t4d0 ONLINE 0 0 0 > c0t5d0 ONLINE 0 0 0 > mirror ONLINE 0 0 0 > c0t6d0 ONLINE 0 0 0 > c0t7d0 ONLINE 0 0 0If c0t6d0 and c0t7d0 both fail (ie both sides of the same mirror vdev) then the pool will be unable to retrieve all the data stored in it. If c0t6d0 and c0t3d0 both fail then there are sufficient replicas of data available in that case because it was disks from different mirrors. This applies to SVM as well if you have a stripe of mirrors with a UFS filesystem ontop of that you will have the same availability issue. -- Darren J Moffat
Darren J Moffat wrote:> If c0t6d0 and c0t7d0 both fail (ie both sides of the same mirror vdev) > then the pool will be unable to retrieve all the data stored in it. If > c0t6d0 and c0t3d0 both fail then there are sufficient replicas of data > available in that case because it was disks from different mirrors. > > This applies to SVM as well if you have a stripe of mirrors with a UFS > filesystem ontop of that you will have the same availability issue. >Thanks for precision :) -- Francois
>>>>> "djm" == Darren J Moffat <darrenm at opensolaris.org> writes:djm> If c0t6d0 and c0t7d0 both fail (ie both sides of the same djm> mirror vdev) then the pool will be unable to retrieve all the djm> data stored in it. won''t be able to retrieve ANY of the data stored on it. It''s correct as you wrote it, but you almost make it sound like you could get some data off the pool, and one might reasonably hope to, but you can''t. for xample, 1. zpool create pool mirror disk1 disk2 2. pax -rwpe /somewhere/else /pool 3. zpool add pool mirror disk3 disk4 [don''t write anything to the pool] 4. [disk3 and disk4 both die] You''ve now lost everything you copied onto the pool in step 2. so, if you type ''zpool add pool disk3 disk4'' and forget the ''mirror'', your mistake isn''t such a small one. You have to quickly find disk5 and disk6 to attach. (happened to me. with <30day-old disk3/disk4. at home with no backup.) -------------- next part -------------- A non-text attachment was scrubbed... Name: not available Type: application/pgp-signature Size: 304 bytes Desc: not available URL: <http://mail.opensolaris.org/pipermail/zfs-discuss/attachments/20080917/4c77f585/attachment.bin>