atom feed19 messages in org.opensolaris.zfs-discuss[zfs-discuss] Does your device honor ...
FromSent OnAttachments
Bryant EadonFeb 10, 2009 10:35 am 
Peter SchullerFeb 10, 2009 10:52 am 
Miles NordinFeb 10, 2009 11:23 am 
Chris RiddFeb 10, 2009 11:27 am 
TimFeb 10, 2009 12:19 pm 
Peter SchullerFeb 10, 2009 1:36 pm 
David Collier-BrownFeb 10, 2009 1:55 pm 
Miles NordinFeb 10, 2009 2:56 pm 
Peter SchullerFeb 10, 2009 3:45 pm 
Bob FriesenhahnFeb 10, 2009 4:08 pm 
Jeff BonwickFeb 10, 2009 4:41 pm 
Toby ThainFeb 10, 2009 5:23 pm 
Miles NordinFeb 10, 2009 6:10 pm 
Frank CusackFeb 10, 2009 7:36 pm 
Toby ThainFeb 10, 2009 8:53 pm 
Bryant EadonFeb 10, 2009 10:28 pm 
Eric D. MudamaFeb 11, 2009 12:25 am 
David Dyer-BennetFeb 11, 2009 7:27 am 
Frank CusackFeb 11, 2009 8:24 am 
Subject:[zfs-discuss] Does your device honor write barriers?
From:Bryant Eadon (
Date:Feb 10, 2009 10:35:39 am


I've been following the thread titled 'ZFS: unreliable for professional use' and I've learned a few things. Put simply, external devices don't behave like internal ones.

From JB :

The good news is that ZFS is getting popular enough on consumer-grade hardware. The bad news is that said hardware has a different set of failure modes, so it takes a bit of work to become resilient to them. This is pretty high on my short list.

from PS : I had a cheap-o USB enclosure that definitely did ignore such commands. On every txg commit I'd get a warning in dmesg (this was on FreeBSD) about the device not implementing the relevant SCSI command.

I use 3 external devices of on 2 models of external enclosures (eSATA and USB consumer grade)-- how can I test this write barrier issue on these 2 ?? Is it worthwhile adding to a wiki (table) somewhere what has or has not been tested ?

Given that ZFS is planned to be used in Snow Leopard, is it worth setting something up for consumer grade appliance vendors to 'certify' against? ("Ok, you play nice with ZFS by doing the right things", etc.. ) Maybe you can give them a 'Gold Star' == 'Supports ZFS' . That'll give them a selling point to consumers and Sun some free marketing ?

Thoughts ?

Thanks, Bryant