Re: [Xen-users] IO is a big difference between the "file" and "phy"

["Fajar A. Nugraha" <list@xxxxxxxxx>]

On Wed, Jun 13, 2012 at 2:59 PM, ÐÑÑÐÐÐ ÐÐÑÐÐÐÐ <ufaweb@xxxxxxxxx> wrote:
> 2012/6/13 Fajar A. Nugraha <list@xxxxxxxxx>
>> That's a known issue.
>>
>> Depending on your configuration, dom0 kernel version, and type of
>> test, file:/ can be MUCH faster, or MUCH slower compared to phy:/, due
>> to interaction of dom0 filesystem, loopback driver, and dom0 kernel
>> cache. ÂBut it shouldn't matter in production environment, as you're
>> NOT supposed to use file:/ anyway, since (on some circumstances) it
>> can cause data corruption.
>
> Ok, but it depends on what

- how large is your test size, relative to dom0 memory
- is the test I/O random or sequential
- does the test use sync/direct I/O
- which fs was used
- how well does the fs handle the underlying storage "lying" about
sync completion

> and how this problem can be solved?

Don't use file:/

-- 
Fajar

_______________________________________________
Xen-users mailing list
Xen-users@xxxxxxxxxxxxx
http://lists.xen.org/xen-users