Re: Multiple varnish instances per server?

2008-06-01 Thread Barry Abrahamson
\On Jun 1, 2008, at 1:38 PM, Michael S. Fischer wrote:

> Why are you using Varnish to serve primarily images?  Modern  
> webservers serve static files very efficiently off the filesystem.

Because we have about 6TB of content and are using Varnish as the  
"hot" cache and S3 as the "cold" store.

--
Barry Abrahamson | Systems Wrangler | Automattic
Blog: http://barry.wordpress.com






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Re: Multiple varnish instances per server?

2008-06-01 Thread Michael S. Fischer
Why are you using Varnish to serve primarily images?  Modern webservers
serve static files very efficiently off the filesystem.
Best regards,

--Michael

On Sun, Jun 1, 2008 at 8:58 AM, Barry Abrahamson <[EMAIL PROTECTED]>
wrote:

> Hi,
>
> Is anyone running multiple varnish instances per server (one per disk
> or similar?)
>
> We are currently running a single varnish instance per server using
> the file backend.  Machines are Dual Opteron 2218, 4GB RAM, and 2
> 250GB SATA drives.  We have the cache file on a software RAID 0
> array.  Our cache size is set to 300GB, but once we get to 100GB or
> so, IO starts to get very spiky, causing loads to spike into the 100
> range.  Our expires are rather long (1-2 weeks).  My initial thoughts
> were that this was caused by cache file fragmentation, but we are
> seeing similar issues when using the malloc backend.  We were thinking
> that running 2 instances per server with smaller cache files (one per
> physical disk), may improve our IO problems.  Is there any performance
> benefit/detriment to running multiple varnish instances per server?
> Is there a performance hit for having a large cache?
>
> Request rates aren't that high (50-150/sec), but the cached files are
> all images, some of which can be rather big (3MB).
>
> Also, is anyone else seeing similar issues under similar workloads?
> --
> Barry Abrahamson | Systems Wrangler | Automattic
> Blog: http://barry.wordpress.com
>
>
>
>
>
>
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Re: Multiple varnish instances per server?

2008-06-01 Thread Poul-Henning Kamp
In message <[EMAIL PROTECTED]>, Barry Abrahams
on writes:
>Hi,
>
>Is anyone running multiple varnish instances per server (one per disk  
>or similar?)

Just remember to set the -n argument to something different.

Poul-Henning

-- 
Poul-Henning Kamp   | UNIX since Zilog Zeus 3.20
[EMAIL PROTECTED] | TCP/IP since RFC 956
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Never attribute to malice what can adequately be explained by incompetence.
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Multiple varnish instances per server?

2008-06-01 Thread Barry Abrahamson
Hi,

Is anyone running multiple varnish instances per server (one per disk  
or similar?)

We are currently running a single varnish instance per server using  
the file backend.  Machines are Dual Opteron 2218, 4GB RAM, and 2  
250GB SATA drives.  We have the cache file on a software RAID 0  
array.  Our cache size is set to 300GB, but once we get to 100GB or  
so, IO starts to get very spiky, causing loads to spike into the 100  
range.  Our expires are rather long (1-2 weeks).  My initial thoughts  
were that this was caused by cache file fragmentation, but we are  
seeing similar issues when using the malloc backend.  We were thinking  
that running 2 instances per server with smaller cache files (one per  
physical disk), may improve our IO problems.  Is there any performance  
benefit/detriment to running multiple varnish instances per server?   
Is there a performance hit for having a large cache?

Request rates aren't that high (50-150/sec), but the cached files are  
all images, some of which can be rather big (3MB).

Also, is anyone else seeing similar issues under similar workloads?
--
Barry Abrahamson | Systems Wrangler | Automattic
Blog: http://barry.wordpress.com






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