You don't mention the technology behind your tape drive, database backend,
CPU, RAM, or what your disk subsystem looks like--all of which would be
useful to have a reasonable chance to analyze even vaguely properly, but
I'll wade in nonetheless.
You are almost certainly shoeshining the heck out of your tape media. I
believe most drive types will have to resort to stopping and starting once
you get below a certain threshold (for LTO3, I think this is somewhere
around 30MB/sec, as an example), the tape drive will wind up starting a
stopping very frequently (as well as rewinding a bit). I imagine this will
wear out both tapes and drive mechanisms pretty quickly.
Since you are not spooling data, I suspect you also are not spooling
attributes--my first guess would be that your database backend is
insufficiently fast--at a minimum you should spool attributes, and spooling
data on even the local backups can yield performance gains, depending on
your disk subsystem architecture. If network and disk subsystem can't
deliver at least the minimum streaming rate for your tape drive, you need
to spool to a fast enough disk to keep up with the tape drives needs.
If you are using something like LTO5, I think spooling using either SSD or
RAID0 may almost be required--but perhaps LTO5 actually supports relatively
low minimum streaming rates--I don't know, as I can't afford LTO5 (and I
think the minimum streaming rate may well be manufacturer dependent).
-se
On Mon, Dec 17, 2012 at 3:47 PM, shockwavecs <bacula-fo...@backupcentral.com
> wrote:
> I'm only seeing around 2MB/s write speed to tape. I have read all about
> spooling the data, etc. I would expect this to be an issue if I was
> complaining about getting 18-25 MB/s instead of 90-100MB/s maybe? Anyways,
> I simply cannot understand why a single job runs at 2 MB/s and 3 jobs will
> run about 2.5MB/s total. See output below (all servers in the same
> rack/switch running at the same time):
>
> Writing: Full Backup job MSSERVER2 JobId=24 Volume="BAL_01"
> pool="Default" device="AIT-4" (/dev/nst0)
> spooling=0 despooling=0 despool_wait=0
> Files=18,121 Bytes=9,726,633,719 Bytes/sec=1,008,254
> FDReadSeqNo=305,615 in_msg=251883 out_msg=5 fd=6
>
> Writing: Full Backup job TS JobId=25 Volume="BAL_01"
> pool="Default" device="AIT-4" (/dev/nst0)
> spooling=0 despooling=0 despool_wait=0
> Files=20,896 Bytes=5,088,180,026 Bytes/sec=691,234
> FDReadSeqNo=256,355 in_msg=195224 out_msg=5 fd=8
>
> Writing: Full Backup job BALDC1 JobId=26 Volume="BAL_01"
> pool="Default" device="AIT-4" (/dev/nst0)
> spooling=0 despooling=0 despool_wait=0
> Files=39,608 Bytes=4,514,041,685 Bytes/sec=658,503
> FDReadSeqNo=411,027 in_msg=295248 out_msg=5 fd=10
>
>
>
> Here is the output of backing up the bacula server itself (this proves
> spooling would not help me, right?):
>
>
> Build OS: i686-pc-linux-gnu redhat
> JobId: 12
> Backup Level: Full (upgraded from Incremental)
> Client: "bacula-fd" 5.2.6 (21Feb12)
> i686-pc-linux-gnu,redhat,
> FileSet: "Full Set" 2012-12-17 11:24:20
> Pool: "Default" (From Job resource)
> Catalog: "MyCatalog" (From Client resource)
> Storage: "SONY" (From command line)
> Scheduled time: 17-Dec-2012 11:24:18
> Start time: 17-Dec-2012 11:24:22
> End time: 17-Dec-2012 12:34:46
> Elapsed time: 1 hour 10 mins 24 secs
> Priority: 10
> FD Files Written: 118,347
> SD Files Written: 118,347
> FD Bytes Written: 8,199,458,340 (8.199 GB)
> SD Bytes Written: 8,215,432,405 (8.215 GB)
> Rate: 1941.2 KB/s
> Software Compression: None
> VSS: no
> Encryption: no
> Accurate: no
> Volume name(s): BAL_01
> Volume Session Id: 1
> Volume Session Time: 1355761332
> Last Volume Bytes: 8,225,667,072 (8.225 GB)
> Non-fatal FD errors: 0
> SD Errors: 0
> FD termination status: OK
> SD termination status: OK
> Termination: Backup OK
> Begin pruning Jobs older than 6 months .
> No Jobs found to prune.
> Begin pruning Files.
> No Files found to prune.
> End auto prune.
>
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>
>
>
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