How to update to 4K alignment safely?

[Noodle]

Hi Forum,

I have a latest freenas server running for pretty long time. It has 6 x 2T RAIDZ (raidz1), 16G RAM. After update to latest 9.2.1 release, I keep getting "One or more devices are configured to use a non-native block size. Expect reduced performance" and "block size: 512B configured, 4096B "native" message in "zpool status". How can I safely update to 4k alignment without lost date?

I'm planning to remove each hard disk, repartition it as 4k aligned, add it back and wait till fully replicated. Will it work?

Thanks

Noodle

 

[HoneyBadger]

Alignment (ashift) is configured at the zpool level, not at each individual device.

The only way to update this is to back up your data, destroy the pool, recreate with ashift=12, and restore.

Alternatively - you can simply ignore it. It's only a warning message, and most people won't ever need the performance they'd gain.

with that said

What you're proposing is also dangerous as you're running RAIDZ1 on six consumer level drives. RAIDZ1 can only tolerate a single drive failure - if you removed a drive and were waiting for it to resilver back, then got a critical error or a panic in the middle of that process, you could very well have a zpool failure.

 

[Noodle]

Thanks for reply.

The message "block size: 512B configured, 4096B native" was showing on each individual hard disk, so I thought it's on disk partition level as well.

It holding over 5T of data now, really hard to backup everything and recreate zpool. I will probably live with it.

Thanks again.

Noodle

Alignment (ashift) is configured at the zpool level, not at each individual device.

The only way to update this is to back up your data, destroy the pool, recreate with ashift=12, and restore.

Alternatively - you can simply ignore it. It's only a warning message, and most people won't ever need the performance they'd gain.

with that said

What you're proposing is also dangerous as you're running RAIDZ1 on six consumer level drives. RAIDZ1 can only tolerate a single drive failure - if you removed a drive and were waiting for it to resilver back, then got a critical error or a panic in the middle of that process, you could very well have a zpool failure.

 

[HoneyBadger]

No problem. Be cautious of the RAIDZ1 issue; I'd suggest you be doing regular backups of anything you consider really critical on that NAS (ie: photos of your kids, not ripped DVDs) just to avoid heartbreak in the future!

 

[cyberjock]

You know... I wrote a sticky on this topic and went into significant detail so you wouldn't have to create ANOTHER thread on the topic. Please see my sticky!

 

[Noodle]

Are you referring to "RAID5/RAIDZ1 is dead"? I didn't see any sticky relate to 4k alignment.

Thanks

You know... I wrote a sticky on this topic and went into significant detail so you wouldn't have to create ANOTHER thread on the topic. Please see my sticky!

 

[HoneyBadger]

He means the 4K alignment issue. Check the "FreeNAS 4 N00bs" subforum, I think its stickied there.

The RAID5/RAIDZ1 is dead is in his sig, and that's what I've been referring to with respect to the need for backups.