Performance of ontape / DLT4000 on AIX ?
Hi,
We have installed a DLT4000 tape on an AIX (4.3.1) system with IDS 7.30.
Taking a level 0 archive using ontape for a 5 GB database takes about 1
hr 50. We have the impression that this is a poor performance
Our current settings for the tape are:
block size (AIX): 1024
BLKSIZE (infx): 256k
Does anyone know the optimal values to be set?
Thanks
--
Helmut Leininger
Bull AG / Vienna
Unix Support
Email: h.leininger@bull.at
helmut.leininger@bull.net
This opinion is mine and not necessarily that of my employer.
No guarantees whatsoever.
In article <36BEBD4C.DB026893@bull.at>,
h.leininger@bull.at wrote:
> Hi,
>
> We have installed a DLT4000 tape on an AIX (4.3.1) system with IDS 7.30.
>
> Taking a level 0 archive using ontape for a 5 GB database takes about 1
> hr 50. We have the impression that this is a poor performance
>
> Our current settings for the tape are:
>
> block size (AIX): 1024
> BLKSIZE (infx): 256k
>
> Does anyone know the optimal values to be set?
>
> Thanks
> --
> Helmut Leininger
>
> Bull AG / Vienna
> Unix Support
> Email: h.leininger@bull.at
> helmut.leininger@bull.net
>
> This opinion is mine and not necessarily that of my employer.
> No guarantees whatsoever.
>
>
Try setting -
AIX blocksize = 10240
TAPEBLK = 10240
We've been able to perform a 13Gb database archive in roughly 1 hour
on AIX 4.2.1 with these settings. Make sure you are using compression mode on
the DLT.
Good luck,
Bob
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Bob Davis wrote:
> In article <36BEBD4C.DB026893@bull.at>,
> h.leininger@bull.at wrote:
> > Hi,
> >
> > We have installed a DLT4000 tape on an AIX (4.3.1) system with IDS 7.30.
> >
> > Taking a level 0 archive using ontape for a 5 GB database takes about 1
> > hr 50. We have the impression that this is a poor performance
> >
> > Our current settings for the tape are:
> >
> > block size (AIX): 1024
> > BLKSIZE (infx): 256k
> >
> > Does anyone know the optimal values to be set?
> >
> > Thanks
> > --
> > Helmut Leininger
> >
> > Bull AG / Vienna
> > Unix Support
> > Email: h.leininger@bull.at
> > helmut.leininger@bull.net
> >
> > This opinion is mine and not necessarily that of my employer.
> > No guarantees whatsoever.
> >
> >
>
> Try setting -
> AIX blocksize = 10240
> TAPEBLK = 10240>
> We've been able to perform a 13Gb database archive in roughly 1 hour
> on AIX 4.2.1 with these settings. Make sure you are using compression mode on
> the DLT.
>
> Good luck,
> Bob
> ----------
>
> -----------== Posted via Deja News, The Discussion Network ==----------
> http://www.dejanews.com/ Search, Read, Discuss, or Start Your Own
Hi Bob,
Thanks for your hint. We changed the AIX blocksize to 0 leaving TAPEBLK at 256.
This accelerated the backup from 1 hr 50 to 12 minutes.
Note:
In your configuration TAPEBLK = 10240 means a block size of 10 MB. Is this really
what you inteded to have ? Do you lucky guy have such much memory?
Regards
Helmut
--
Helmut Leininger
Bull AG / Vienna
Unix Support
Email: h.leininger@bull.at
helmut.leininger@bull.net
This opinion is mine and not necessarily that of my employer.
No guarantees whatsoever.
yeah, this is a wee bit slow, What about using onbar instead? It runs the
backup in parallel.
The other thing is, SCSI devices are often 16bit so 32Kb or 64Kb block sizes
might be better.
Helmut Leininger wrote:
> Hi,
>
> We have installed a DLT4000 tape on an AIX (4.3.1) system with IDS 7.30.
>
> Taking a level 0 archive using ontape for a 5 GB database takes about 1
> hr 50. We have the impression that this is a poor performance
>
> Our current settings for the tape are:
>
> block size (AIX): 1024
> BLKSIZE (infx): 256k
>
> Does anyone know the optimal values to be set?
>
--
Colin Smith
Cellular Subscriber Sector Europe
Colin_Smith@euro.css.mot.com
Phone: +44 (0)1256 790 261