Re: [Veritas-bu] Sizing experiences ?

You didn't specify the OS either. You're going to need some serious staging units since you have 400MB of theoretical bandwidth in and about twice that out to tape. You either have too many tape drives or they're going to be underutilized.

No matter what OS, that memory seems awfully tight. I wouldn't touch that config with under 16GB of memory. Instead of 8 LTO-3 drives on a single master/media server, you should probably split that up into separate master and media servers.

Do the I/O calculations very, very carefully. You're probably not going to be able to pull that config off with any Windows server I've seen - you'll starve those tape drives since you likely won't even have enough HBA bandwidth to drive them. You're far better off driving 4 LTO-3 drives at full speed than 8 drives at a slow, shoe-shining speed.

What kills most environments is not CPU but I/O. Don't just assume that your disk I/O is adequate - we see destaging performance plummet when we write to the same disk at the same time.

.../Ed

On Wed, Mar 26, 2008 at 11:06 AM, Michael Graff Andersen <mian71 AT gmail DOT com> wrote:

Oops, didn't write that the master/media server will have 4x 1 Gbit
NICs & 8x LT03 tape drives. Using the document I arrived at 8 CPUs &
4.6 GB RAM

Trying to get a server that can handle the NICs & tape drive at full
tilt & peoples experiences with using this document or other methods
of sizing

Regards
Michael

2008/3/26, Ed Wilts <ewilts AT ewilts DOT org>:

> On Wed, Mar 26, 2008 at 10:26 AM, Michael Graff Andersen <mian71 AT gmail DOT com>
> wrote:
>
> > We are about to replace our backup server and I have used the Backup
> > Planning and Performance Tuning Guide for 6.0 to size our new server
> >
> > Our server people think the sizing is wrong, more specifically that it
> > gives to many CPUs
> >
> > What are you experience regarding sizing ?
>
> Rule #1. There's no such thing as "too many CPUs or too much memory".
> Rule #2. See Rule #1
> Rule #3. Is your storage growing? If it is, see rule #1.
>
> In general, the master server needs lots of memory and cpu and the media
> servers need less memory but lots of I/O bandwidth. All of them need
> plenty of disk space for logs - 20-50GB at a minimum and in a busy
> environment while troubleshooting issues, 100GB of logs is not unheard of.
> Without significantly more details on what exactly you're trying to
> accomplish and what config you came up with, we're not going to be able to
> get more specific than that.
>
> .../Ed
>
> --
> Ed Wilts, Mounds View, MN, USA
> mailto:ewilts AT ewilts DOT org

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--
Ed Wilts, Mounds View, MN, USA
mailto:ewilts AT ewilts DOT org

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