On 2/12/19 7:01 AM, Claas Goltz wrote: > Hi, is it technically possible to spool and despool at the same > time?
Kind of. You can have multiple backup jobs writing to the spool area at once. This is controlled by the 'maximum concurrent jobs' in the job (I do it in the jobdef) section. But you really only want one job despooling at a time, which I control via the 'maximum concurrent jobs' in the storage section. But in Bareos a job isn't done until the data is written to storage AND the catalog is updated. But it isn't perfect. As Andi said that disk bandwidth especially when trying to keep modern LTO tapes streaming can limit the writes you can do. We run into that with a dedicated server and a 12 disk array trying to do both virtual full backups and keeping the tape drive fed. We do this for a hundred or so virtual full backups where we build the spool on-disk and then de-spool to tape. Here are averages for different concurrency settings for building spool files. All de-spools happen one at a time. concurrency 10 -- Average time 5.64 hours, avg tape speed 112.9 MB/s concurrency 5 -- Average time 6.08 hours, avg tape speed 124.2 MB/s concurrency 3 -- Average time 6.69 hours, avg tape speed 131.5 MB/s As you can see that the concurrency saves you some time, but not a lot. And tape speed increases quite a bit. In a few weeks I'm going to start testing with a concurrency of 2. And then a few months later down to 1. I suspect that I'll end up somewhere around the 1 to 3 range eventually. -- You received this message because you are subscribed to the Google Groups "bareos-users" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. For more options, visit https://groups.google.com/d/optout.
