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From: Daniel Stodden <daniel.stodden@citrix.com>
To: John Weekes <lists.xen@nuclearfallout.net>
Cc: Ian Pratt <Ian.Pratt@eu.citrix.com>,
	"xen-devel@lists.xensource.com" <xen-devel@lists.xensource.com>
Subject: Re: OOM problems
Date: Sun, 14 Nov 2010 01:53:06 -0800	[thread overview]
Message-ID: <1289728386.11857.22.camel@ramone> (raw)
In-Reply-To: <4CDE6639.2070509@nuclearfallout.net>

On Sat, 2010-11-13 at 05:19 -0500, John Weekes wrote:
> On 11/13/2010 1:13 AM, Ian Pratt wrote:
>  > Ah, if you're using loop it may be that you're just filling memory 
> with dirty pages. Older kernels certainly did this, not sure about newer 
> ones.
>  > I'd be inclined to use blktap2 in raw file mode, with "aio:".
> 
> With blktap2, is free RAM in dom0 still used for a disk cache at all? I 
> have this dom0 set to 1.5 GB mainly to help with caching; if that RAM is 
> not needed, I'll retool it down to a smaller number.

If you're not using cloned images deriving from a shared parent image,
that caching won't buy anyone much. Memory better spent on the guests
themselves then, thereby their own caches. 

Keep an eye on /proc/meminfo, it largely depends on number/type of
guests, but probably safe to reassign ~800M straight away.

blktap2 with aio will move the datapath to direct I/O. Comparend to
buffered loops, there's also some notable benefit to crash consistency
resulting from that.

Daniel

  reply	other threads:[~2010-11-14  9:53 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-11-13  7:57 OOM problems John Weekes
2010-11-13  8:14 ` Ian Pratt
2010-11-13  8:27   ` John Weekes
2010-11-13  9:13     ` Ian Pratt
2010-11-13  9:43       ` John Weekes
2010-11-13 10:19       ` John Weekes
2010-11-14  9:53         ` Daniel Stodden [this message]
2010-11-15  8:55       ` Jan Beulich
2010-11-15  9:40         ` Daniel Stodden
2010-11-15  9:57           ` Jan Beulich
2010-11-15 17:59           ` John Weekes
2010-11-16 19:54             ` John Weekes
2010-11-17 20:10               ` Ian Pratt
2010-11-17 22:02                 ` John Weekes
2010-11-18  0:56                   ` Ian Pratt
2010-11-18  1:23                   ` Daniel Stodden
2010-11-18  3:29                     ` John Weekes
2010-11-18  4:08                       ` Daniel Stodden
2010-11-18  7:15                         ` John Weekes
2010-11-18 10:41                           ` Daniel Stodden
2010-11-19  7:27                             ` John Weekes
2010-11-15 14:17         ` Stefano Stabellini
2010-11-13 18:15 ` George Shuklin

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