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Re: [Qemu-devel] iSCSI support for QEMU
From: |
ronnie sahlberg |
Subject: |
Re: [Qemu-devel] iSCSI support for QEMU |
Date: |
Fri, 22 Apr 2011 06:25:26 +1000 |
On Thu, Apr 21, 2011 at 10:49 PM, Christoph Hellwig <address@hidden> wrote:
> On Thu, Apr 21, 2011 at 09:36:12PM +1000, ronnie sahlberg wrote:
>> There are some high-volume arrays that advertise support but fail any
>> cdb with FUA, FUA_NV bits set with sense, so it needs to be made optional.
>
> Which on would that be? Linux uses the FUA bit if the device advertises
> support
> via the DPOFUA bit since 2005, and prints a warning if a FUA write fails,
> and since last year even fails the request hard. I'd be really surprised
> if a common device fails FUA writes and we didn't know about it by now.
>
> Either way you'll have to still guarantee data made it to non-volatile
> storage for cache=writethrough mode, either by disabling the WCE bit
> using MODE SELECT, or by flushing the cache after every write.
>
Thankyou for your patience.
I understand and I have updated the patch to set FUA when the _WB flag
is not set.
regards
ronnie sahlberg
- Re: [Qemu-devel] iSCSI support for QEMU, (continued)
- Re: [Qemu-devel] iSCSI support for QEMU, ronnie sahlberg, 2011/04/21
- Re: [Qemu-devel] iSCSI support for QEMU, Christoph Hellwig, 2011/04/21
- Re: [Qemu-devel] iSCSI support for QEMU, ronnie sahlberg, 2011/04/21
- Re: [Qemu-devel] iSCSI support for QEMU, Stefan Hajnoczi, 2011/04/21
- Re: [Qemu-devel] iSCSI support for QEMU, ronnie sahlberg, 2011/04/21
- Re: [Qemu-devel] iSCSI support for QEMU, Stefan Hajnoczi, 2011/04/21
- Re: [Qemu-devel] iSCSI support for QEMU, ronnie sahlberg, 2011/04/21
- Re: [Qemu-devel] iSCSI support for QEMU, Kevin Wolf, 2011/04/21
- Re: [Qemu-devel] iSCSI support for QEMU, Stefan Hajnoczi, 2011/04/21
- Re: [Qemu-devel] iSCSI support for QEMU, Christoph Hellwig, 2011/04/21
- Re: [Qemu-devel] iSCSI support for QEMU,
ronnie sahlberg <=
- Re: [Qemu-devel] iSCSI support for QEMU, ronnie sahlberg, 2011/04/21