On Wed, Dec 06, 2006 at 04:33:16PM -0600, Evan Harris wrote:
>
> Debian testing, SDLT 110/220, Intel P4 2.8Ghz 3gig RAM. Amanda 2.5.1p1-2.
>
> The holding disk is a dedicated PATA IDE drive (master) on its own
> cable/bus (no slave). The tape drive is on its own SCSI bus (no other
> devices). Bonnie tests on the IDE drive give roughly 20MB/sec, and I have
> no trouble keeping the tape drive streaming using dd from the IDE drive to
> the tape drive. Amanda tapetest speed on the tapedrive came in right at
> 10MB/sec.
I have an SDLT 220 also, mine being set for high density but without
HW compression, I specifically perform SW compression (client side though
in this case the client==server). I am also peaking about 10MB/sec per
the amdump report.
I have to look at the tape specs... Sun online docs show a sustained
transfer rate of 11 MB/Sec, so you and I are both doing pretty well
in that dept.
Tell me again why you feel your drive is shoe-shining ?
Are the specs for your particular drive substantially different ?
> I'm currently testing on a standalone SDLT drive first. But the final
> config will be the same type of drive in an ADIC changer.
>
> Evan
>
> On Wed, 6 Dec 2006, Brian Cuttler wrote:
>
> >Evan,
> >
> >What OS, type of tape, type of drive, HW platform ?
> >
> >I'm unfamiliar with a parameter to do what your asking
> >for for good measure, what version of Amanda ?
> >
> >Actually, how did you determine that a drive within a changer
> >was shoe-shining ? What else shares the bus with the tape and
> >with the amanda work area drive(s) ?
> >
> >On Wed, Dec 06, 2006 at 02:34:31PM -0600, Evan Harris wrote:
> >>
> >>I'm having a problem with my tape drive shoe-shining because the holding
> >>disk can't keep up with the tape drive if it is also being written to by a
> >>dumper. Without the extra disk seek overhead of dumpers writing to the
> >>holding disk at the same time, the holding disk should be plenty fast
> >>enough to keep the tape drive streaming.
> >>
> >>Is there any way I can force amanda to serialize the dumper/taper so that
> >>they are never run concurrently? I've already set inparallel to 1, but
> >>that only affects how many dumpers can run, not the taper.
> >>
> >>I've also tried increasing the tapebufs parameter to 8000 (256MiB) to see
> >>if that would at least let the drive stay streaming for longer periods,
> >>but
> >>if it made any difference, it wasn't significant. What thresholds does
> >>the
> >>taper use to decide when the tapebufs are filled enough to start tape
> >>motion? There doesn't seem to be any docs on that, or settings to
> >>customize.
> >>
> >>I did get a suggestion that I should just leave the tape out of the drive,
> >>let the dumpers fill the holding disk and then load the tape and run
> >>amflush, but that doesn't really work when using a changer, plus the
> >>holding disk isn't large enough for the total size of all the backups,
> >>though it can fit them one-by-one.
> >>
> >>Seems like there should be a "speed" config option for holding disks like
> >>there is for network interfaces and tape drives, so that amanda could test
> >>to see if the holding disk can't handle dumpers using the holding disk at
> >>the same time a taper is running. That seems like it'd solve the problem
> >>nicely, and even seems to fit with the scheme amanda uses for network
> >>interfaces.
> >>
> >>Thanks.
> >>
> >>Evan
> >---
> > Brian R Cuttler brian.cuttler AT wadsworth DOT org
> > Computer Systems Support (v) 518 486-1697
> > Wadsworth Center (f) 518 473-6384
> > NYS Department of Health Help Desk 518 473-0773
> >
---
Brian R Cuttler brian.cuttler AT wadsworth DOT org
Computer Systems Support (v) 518 486-1697
Wadsworth Center (f) 518 473-6384
NYS Department of Health Help Desk 518 473-0773
|
