On Tuesday 28 July 2009 16:46:43 Alan Brown wrote: > On Tue, 28 Jul 2009, Marc Cousin wrote: > > At peak during the night, we have around 40-50 write streams at the same > > time, and we are despooling to 3 LTO3 and 3 LTO1. > > That's larger than my installation and I haven't got budget for a > dedicated array controller. We're using software striping on our disks.
I thought so. All I wanted to say was that I think that with proper tuning, there is no real need for SSD in this context. I had to use an array for two reasons : - I needed extra capacity : for some jobs, we spool more than one terabyte of data before despooling to tape - Anyway, SDD costed a lot, 2 years ago SSD wont suck, but they won't be a silver bullet either. > > > I think the most important is : don't purchase anything without doing > > benchmarks first for this special type of activity. That's what we did : > > we wrote a small program to simulate the expected throughput on the array > > with several streams, and only bought the array when we were satisfied > > with its performance, which required a bit of tuning (choose the right > > filesystem, the right scheduler, tune read ahead...). And I think this > > time wasn't wasted at all... > > You're right, it isn't. > > The main criterion is keeping up with the tape drive(s). Right now we are, > but that will change with a new robot purchase and that's why I'm looking > ahead. You'll need to despool in quite small chunks then. Not that it really is a problem, it's just that we tend to despool a job when it is finished if possible, and for that we need a lot of capacity. ------------------------------------------------------------------------------ Let Crystal Reports handle the reporting - Free Crystal Reports 2008 30-Day trial. Simplify your report design, integration and deployment - and focus on what you do best, core application coding. Discover what's new with Crystal Reports now. http://p.sf.net/sfu/bobj-july _______________________________________________ Bacula-users mailing list Bacula-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bacula-users
