Replace old HD with 4k Sector New Hard disk - Possible?

[Corban987]

Hi

I was wondering if it was possible to replace a drive in a ZFS array that was created with old non 4k sector drives with the new 4k sector drives. I have searched looking for an answer and not sure if this has been asked before. If I only lose performance then I can live with that for now.

My array is made up of the following (They were all originally WD drives, but they are the ones failing, I had found in the past some Seagate drives but I can't get them anymore). My ZFS pool is an old version but I am not willing to upgrade that until I have a stable array. I am getting retry on ADA5 which ends up failing and bringing down the machine, a reboot fixes it for a few hours/days (RANDOM)

ada0 1430800MB ST31500341AS/CC1H ST31500341AS 9VS2JWLT 60 ZFS storage pool device ONLINE
ada1 1430800MB WDC WD15EADS-00P8B0/01.00A01 WDC WD15EADS-00P8B0 WD-WMAVU0073746 60 ZFS storage pool device ONLINE
ada2 1430800MB WDC WD15EADS-00R6B0/01.00A01 WDC WD15EADS-00R6B0 WD-WCAVY0958971 60 ZFS storage pool device ONLINE
ada3 1430800MB ST31500541AS/CC34 ST31500541AS 9XW01HAW 60 ZFS storage pool device ONLINE
ada4 1430800MB ST31500341AS/CC1H ST31500541AS 9XW09V56 60 ZFS storage pool device ONLINE
ada5 1430800MB WDC WD15EADS-00S2B0/01.00A01 WDC WD15EADS-00S2B0 WD-WCAVY1579009 60 ZFS storage pool device ONLINE

pool: tank
state: ONLINE
status: The pool is formatted using an older on-disk format. The pool can
still be used, but some features are unavailable.
action: Upgrade the pool using 'zpool upgrade'. Once this is done, the
pool will no longer be accessible on older software versions.
scan: resilvered 560M in 7h20m with 0 errors on Sat Jun 8 18:08:33 2013
config:

NAME STATE READ WRITE CKSUM
tank ONLINE 0 0 0
raidz1-0 ONLINE 0 0 0
ada0 ONLINE 0 0 0
ada1 ONLINE 0 0 0
ada2 ONLINE 0 0 0
ada3 ONLINE 0 0 0
ada4 ONLINE 0 0 0
ada5 ONLINE 0 0 0

errors: No known data errors

[siftu]

You can replace it with a 4k drive and it will hurt performance by up to 30%. But it will work..

If your drives are all the same age and failing then I would consider creating a new pool with a new vdev and use the advanced format on the vdev.. You can even create a couple of vdevs, one with 512b sector drives and another with 4k drives and add them to the same pool.

[Corban987]

Thanks, I am not sure I 100% follow. Would this mean each of my HD's would be a a VDEV, each with its own format (ie the old drives would be the 512b and the new own 4k), then add these VDEV's to my pool as a RAIDZ_1 array?

[siftu]

Well you would think about restructuring your pool/virtual devices.. Maybe you would go with 2xRAIDZ in the same pool, one made of 512b drives and the other made out of 4k drives. i.e. your old drives in a raidz not using advanced format, and new drives in a raidz using advanced format. That might mean you have to buy a few more drives, but it's an option.