Cyrus infrastructure performance less than expected

[Eric Déchaux]

Rob Mueller a écrit :
>> On current production platform the frontends use swap massively but the
>> impact is far less than on the new platform.
>>     
>
> It's not so much how much swap is actually used, but how much is being paged 
> in or paged out at any time. If there are memory pages not being used at 
> all, the OS will swap them out, but that's fine because they're not being 
> used.
>
> The problem is when more memory pages are being used than memory available. 
> In that case the OS starts continuously moving things back and forth between 
> RAM and swap, which causes performance to become horrible.
>
> Can you run "free" and "vmstat 10 10" (will take 100 seconds to run) on one 
> of your old frontends and one of your new frontends during peak times so we 
> can get an idea of what is going on with memory + swap.
>
> Also lets just confirm a process count on your system. Run these commands:
>
> ps ax | wc -l
> ps ax | grep imapd | wc -l
>
> On both old and new.
>
>   
>> We are indeed using 64bits OS and 64bits software. This is the main
>> difference between the old platform which runs a 32 bits software on a
>> 32 bits OS.
>>     
>
> That will increase memory usage as well. Every pointer in the system (either 
> in the kernel or in an application) is now using twice as much space. Of 
> course not all data is pointers, but depending on the application it can 
> mean considerably more memory is used.
>
> Lets start with the free, vmstat and ps data, and we'll go from there.
>
>   
We are currently gathering those data. They will be posted when available.
Setting the TLS cache db to skiplist remove the locking errors we had.

--
Eric