On 12/3/2014 8:12 AM, Daniel Pocock wrote: > Can anybody make any practical comments on how to choose a suitable > spool disk (both speed, size and whether to make an array of disks for > spooling)? > > It would be useful to see some examples of spooling for LTO-3 up to > LTO-6 and also any comments about things to avoid > > For example, if somebody uses LTO-3 (400GB, supporting 60 - 80MB/sec) > will a single SSD sustain the necessary speed de-spooling to tape or > should multiple SSDs be used in RAID0 or RAID1? Is it feasible for > clients to be spooling more jobs to the same disk simultaneously while > the tape drive is reading from it?
A single SSD such as the Intel Fultondale series will sustain average read speeds far in excess of the LTO-6 400 MB/s maximum. A Lyndonville series will sustain average read speeds of around 200 MB/s. But you have to compare apples to apples. The maximum write speed of LTO-6 is 400 MB/s, but what is the average write speed after writing many blocks for a whole job? A single Lyndonville drive may suffice, or a RAID array of SAS drives. I stay away from RAIDing SSDs and won't use RAID0 for anything. Also, in addition to de-spooling data to tape, it must also de-spool metadata to the database. IMO, the SSD makes far more difference for the database than for the spool. ------------------------------------------------------------------------------ Download BIRT iHub F-Type - The Free Enterprise-Grade BIRT Server from Actuate! Instantly Supercharge Your Business Reports and Dashboards with Interactivity, Sharing, Native Excel Exports, App Integration & more Get technology previously reserved for billion-dollar corporations, FREE http://pubads.g.doubleclick.net/gampad/clk?id=164703151&iu=/4140/ostg.clktrk _______________________________________________ Bacula-users mailing list Bacula-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bacula-users