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<TITLE>Re: [Openstack] Caching strategies in Nova ...</TITLE>
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<FONT FACE="Calibri, Verdana, Helvetica, Arial"><SPAN STYLE='font-size:11pt'>Right,<BR>
<BR>
Lets fix the problem, not add a patch that hides the problem.<BR>
<BR>
U can’t put lipstick on a pig, haha. Its still a pig...<BR>
<BR>
On 3/22/12 8:02 PM, "Mark Washenberger" <<a href="mark.washenberger@rackspace.com">mark.washenberger@rackspace.com</a>> wrote:<BR>
<BR>
</SPAN></FONT><BLOCKQUOTE><FONT FACE="Calibri, Verdana, Helvetica, Arial"><SPAN STYLE='font-size:11pt'>This is precisely my concern.<BR>
<BR>
It must be brought up that with Rackspace Cloud Servers, nearly<BR>
all client codes routinely submit requests with a query parameter<BR>
"cache-busting=<some random string>" just to get around problems with<BR>
cache invalidation. And woe to the client that does not.<BR>
<BR>
I get the feeling that once trust like this is lost, a project has<BR>
a hard time regaining it. I'm not saying that we can avoid<BR>
inconsistency entirely. Rather, I believe we will have to embrace<BR>
some eventual-consistency models to enable the performance and<BR>
scale we will ultimately attain. But I just get the feeling that<BR>
generic caches are really only appropriate for write-once or at<BR>
least write-rarely data. So personally I would rule out external<BR>
caches entirely and try to be very judicious in selecting internal<BR>
caches as well.<BR>
<BR>
"Joshua Harlow" <<a href="harlowja@yahoo-inc.com">harlowja@yahoo-inc.com</a>> said:<BR>
<BR>
> _______________________________________________<BR>
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> Just from experience.<BR>
><BR>
> They do a great job. But the killer thing about caching is how u do the cache<BR>
> invalidation.<BR>
><BR>
> Just caching stuff is easy-peasy, making sure it is invalidated on all servers in<BR>
> all conditions, not so easy...<BR>
><BR>
> On 3/22/12 4:26 PM, "Sandy Walsh" <<a href="sandy.walsh@rackspace.com">sandy.walsh@rackspace.com</a>> wrote:<BR>
><BR>
> We're doing tests to find out where the bottlenecks are, caching is the<BR>
> most obvious solution, but there may be others. Tools like memcache do a<BR>
> really good job of sharing memory across servers so we don't have to<BR>
> reinvent the wheel or hit the db at all.<BR>
><BR>
> In addition to looking into caching technologies/approaches we're gluing<BR>
> together some tools for finding those bottlenecks. Our first step will<BR>
> be finding them, then squashing them ... however.<BR>
><BR>
> -S<BR>
><BR>
> On 03/22/2012 06:25 PM, Mark Washenberger wrote:<BR>
>> What problems are caching strategies supposed to solve?<BR>
>><BR>
>> On the nova compute side, it seems like streamlining db access and<BR>
>> api-view tables would solve any performance problems caching would<BR>
>> address, while keeping the stale data management problem small.<BR>
>><BR>
><BR>
> _______________________________________________<BR>
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><BR>
><BR>
<BR>
<BR>
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