Am Dienstag, 12. Februar 2019 15:33:05 UTC+1 schrieb Douglas Rand: > 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.
Thank you so much. I didnt think about concurrent job settings in different locations. I will play around with that. regarding spooling device: i'm in the glad position, that I can deal with an NVME SSD, so there should not be an bandwith limit. -- 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.
