Re: [Veritas-bu] General questions for everyone

On 11/2/07, Cruice, Daniel (US - Glen Mills) <dcruice AT deloitte DOT com> wrote:

WOW…good info…I should be a little clearer, on my media servers (we have 7) they are Gig Fiber direct runs to the backup network core…the majority of my clients are 100mb due to old switches. So the speed from media server to tape is Gig…SAN attached. We have been running in the neighborhood of 3000 – 7000 KB/sec, which is pretty good.

Actually, 3MB - 7MB per second is pretty horrible, especially for LTO-3 drives. You need to get 10x that and you can if you configure your environment properly. Most of us aren't consistently getting 70MB/sec (I do for some jobs), but a minimum of 20MB/sec consistently should be expected.

If you have your clients running at 900-1000KBps, then 20 of them total 18-20MB/sec. That's not nearly enough to get decent performance out of an LTO-3.

And yes we did need to perform a recovery exercise…it was basically a Disaster Recovery when our SAN decided to crash due to a power outage and a faulty UPS subsequently corrupting a few TB of SAN data. And yes recovery effort was slow since we may have had 10 – 20 jobs on the same tape about 150 servers over 3 (12 hour) days. Yea painful, very painful. We are looking to move that 20 number down and still keep the backups in our window. Tedious process but it is being worked on.

One really good way, as somebody else pointed out, is to use disk staging. That allows you to multiplex like crazy on your backups, but by design, the data is de-multiplexed writing to tape. That means that full-system restores will be significantly faster - each image will be contiguous on tape.

.../Ed

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

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