Linux, gobs of RAM, RAID and performance suckage...

[Neil Joseph Schelly]

On Thursday 30 November 2006 01:51 pm, Paul Lussier wrote:

> It's not a SAN.  It's direct-attached storage.

> > Winchester OpenSAN FC-based RAID array

Isn't this the storage?  I assume the description meant it was a SAN.  What is 
the topology of that FC network?

> In theory, yes, in practicality, no.  Also, the backups are not
> "touching the NFS server".
>
> Amanda connects to the amanda daemon on space-monster (via inetd) and
> requests that he start his backup process.  space-monster in turn
> kicks off a gtar process which sends the data back to amanda.  The
> gtar process is reading the local disk, not NFS.  Apparently, this
> local disk I/O request supercedes NFS disk requests.  But there's much
> more than that happening here.  CPU utilization is through the roof on
> space-monster.  That wasn't the case yesterday before the memory
> upgrade.

It sounds like the NFS server, space-monster in your description, is having to 
read all that data from the filesystem and send all that data to the backup 
server called amanda in your description.

If you could put another server on the SAN, in the FC network, that machine 
could also mount the partition (read-only obviously) on the SAN and backup 
the contents without the space-monster even knowing anything is happening.
-N