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<font size="-1">Hi Hitoshi,<br>
<br>
as long as the object cache doesn't work relieable my setup doesn't
make sense, because of the slow network connections (only
200MBit/s).<br>
<br>
This will only work if most reads and writes are statisfied by the
local object cache. If every read and write goes through the
network, than performance will be very poor.<br>
<br>
At the moment I have only 2 storage nodes and 3 gateways with 6
VMs for testing (and object cache turned on). This works fine, but
as you say that object cache should not be used, this setup will
not scale (in the end there will be about 100 VMs on 8-10 nodes).<br>
<br>
I need something that allows me such a setup over slow network
connections. This mean that must be some cacheing and an
asynchronous write back. For the kind of VMs I am running it's ok,
if some data is lost in case of failure.<br>
<br>
Sheepdog with object cache looked very promising for such a setup.
I didn't found any other solution so far.<br>
<br>
Regards<br>
<br>
Gerald<br>
<br>
</font><br>
<div class="moz-cite-prefix">Am 09.11.2015 um 05:01 schrieb Hitoshi
Mitake:<br>
</div>
<blockquote
cite="mid:CAE1WaKJZz13CFgDi_KgCLHm4x7oMND9XcNjqLhWcb00mvN2rrg@mail.gmail.com"
type="cite">
<pre wrap="">Hi Gerald,
On Sat, Nov 7, 2015 at 9:05 PM, Gerald Richter <a class="moz-txt-link-rfc2396E" href="mailto:richter@ecos.de"><richter@ecos.de></a> wrote:
</pre>
<blockquote type="cite">
<pre wrap="">Hi,
I need to setup a storage cluster over slow network connections.
Sheepdog in gateway mode seems to be the ideal solution for me. That mean I
have three or more storage nodes and a lot of gateway node that only uses
the sheepdog cache. As long as most request are statisfied by the cache
(which is an ssd), performance should be ok. Slow network connection aren't
a problem as long as the cache uses write back mode.
I have setup a test environment with 0.9.2 . As long as the vm are small
enough to fit completly in the cache it seems to work, but when the vm is
bigger than the cache I get I/O errors after some time. Also after a reboot
of the host machine it seems to take very long time, until I can boot the
vm, also the cache is still uptodate.
Browseing through the mailing list archive I found
<a class="moz-txt-link-freetext" href="http://lists.wpkg.org/pipermail/sheepdog-users/2015-August/015120.html">http://lists.wpkg.org/pipermail/sheepdog-users/2015-August/015120.html</a>,
where Hitoshi said "object cache is not maintained currently. Please do not
use it.". Is this still true? or is there any way to use the setup I
described above?
</pre>
</blockquote>
<pre wrap="">
Yes, it's true. Please don't use object cache.
BTW, many gateways + fewer storage nodes is dangerous. Because the
gateways doesn't contribute to increasing parallelism of disk I/O. If
a number of VMs and storage nodes are unbalanced, performance of
virtual disks will be very bad. Could you provide a detailed number of
VMs, gateway nodes, and storage nodes?
Thanks,
Hitoshi
</pre>
<blockquote type="cite">
<pre wrap="">
Thanks & Regards
Gerald
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</pre>
</blockquote>
<pre wrap="">
!DSPAM:416,56401a9a23791711617062!
</pre>
</blockquote>
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