RAM RAM RAM! 512MB of ram is definitely your issue here. swapping causes
more periods of head movement which means less periods of head reads/writes
on your disk. With your specs, moving to 1GB+ of ram will be huge.
that Celeron processor is probably your next big issue specifically because
it has less cache memory than a Core2 or Athlon which is a BIG hit on any
kind of compression as well as requiring more trips to main memory, which
makes any transaction that is larger than the cache go to main memory and
back with is 100x longer than a level1 cache retrieval.
a dual core processor will help a lot with multiple client backups but i
would just go dual core unless you are going to get a scsi/sas raid5 card
and get really serious. a quad core cpu would be choice for such a setup
but on slower/standard hard disks a dual core is perfect.
1)get another GB of ram
2)get a CPU with more cache. that celeron likely has 256KB of cache. I
have a new e8400 core2 duo with 6MB cache and it is smoking fast running
backuppc. I don't run it in production but i have done some tests and that
cache memory and 2x3Ghz CPU cores improves the speed of compression a lot.
3)the disk is somewhat of a hard limit here, you can get faster disks but to
get big, fast, redundant disks will cost money. the RAM and CPU will likely
make you pretty happy in the short-to-medium term.
good luck
On Wed, Feb 27, 2008 at 5:38 PM, Stephen Joyce <[EMAIL PROTECTED]>
wrote:
> On Wed, 27 Feb 2008, John Pettitt wrote:
>
> > So my take - if your box is swapping that's the #1 upgrade because that
> > will kill any server performance and memory is cheap. Next I'd look at
> > disk, with the right controller more spindles will give you a
> > performance boost however raid 5 is not a great way to go because of the
> > cost of doing write splices.
>
> (Mostly) agreed. If you can afford a hardware raid controller, raid 5 is a
> good choice. If money is no object, 3ware cards are great, but they're not
> the only choice. My backups are running on a couple of older SCSI <-> xATA
> HW raid controllers (Arena and Promise) and they work great because the
> parity computation is handled by the raid's processor rather than the
> server's.
>
> My bottleneck right now is still disk, but I can do 4 simultaneous
> backups on a dual 2.8 xeon HT w/ 2.5 GB of RAM (CPU and RAM are both
> probably overkill) before hitting it.
>
> > Lastly CPU unless you are running with a load average close
> > to or greater than the # of cpu's it's probably not going to gain you
> much.
>
> CPU seems to have a larger correlation with the number of clients you can
> handle at once. In my experience it's not a great idea to ask the server
> to
> handle much more than one client per CPU core; your mileage may vary
> depending on what your CPU core(s) and transfer method are though.
>
> Cheers, Stephen
> --
> Stephen Joyce
> Systems Administrator P A N I C
> Physics & Astronomy Department Physics & Astronomy
> University of North Carolina at Chapel Hill Network Infrastructure
> voice: (919) 962-7214 and Computing
> fax: (919) 962-0480 http://www.panic.unc.edu
>
> Don't judge a book by its movie.
>
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