Right, but the data does exist. What I'm wondering is if it will treat the
sparse image file as 1 file, or will it cache on a block basis.
> Do you often read holes from sparse?
I'm not sure how to answer that.
-----Original Message-----
From: xen-users-bounces@xxxxxxxxxxxxxxxxxxx
[mailto:xen-users-bounces@xxxxxxxxxxxxxxxxxxx] On Behalf Of George Shuklin
Sent: Thursday, July 08, 2010 4:36 PM
To: xen-users@xxxxxxxxxxxxxxxxxxx
Subject: Re: [Xen-users] Xen Sparse Image Files and MaxIQ SSD
That's simple: caching only if data exists.
All 'holes' in spare file does not exists. They are just opinion of filesystem,
but on block level there is no sparse.
One more: MaxIQ cache most reed data. Do you often read holes from sparse?
В Чтв, 08/07/2010 в 16:08 -0500, Andy Pace пишет:
> Hello list!
>
>
>
> I’m currently storing Xen sparse image files for VM’s on remote
> attached storage devices, and looking to increase the amount of IO
> available on it. I’ve ran across MaxIQ SSD read acceleration caching,
> and was wondering if this is a smart move, given the way we use the
> sparse image files.
>
>
>
> My fear is that the MaxIQ will cache entire image files, instead of
> the most commonly accessed files *INSIDE* the VM. Can anyone confirm
> or deny my theory?
>
>
>
> I’ve talked with Adaptec and this is what they told me:
>
>
>
> --------
>
> It's hard to say exactly. Keep in mind that a RAID card isn't aware of
> files, only blocks. So depending on how the blocks are accessed, the
> MaxIQ product may or may not help you. My first impression with 30GB
> files is that it may not be very helpful.
>
> --------
>
>
>
> So, that being said, right now we are accessing the image files using
> the ‘file’ mode:
>
>
>
> <disk type='file' device='disk'>
>
> <driver name='file'/>
>
> <source file='/distributed/vms/29609/disk.img'/>
>
> <target dev='xvda' bus='xen'/>
>
> </disk>
>
>
>
> Will the MaxIQ work in the way I want it to, or will I have to change
> the way we access the images? Or will it end up trying to cache entire
> images onto the SSD? Has anyone had experience with this type of
> application?
>
>
> _______________________________________________
> Xen-users mailing list
> Xen-users@xxxxxxxxxxxxxxxxxxx
> http://lists.xensource.com/xen-users
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