* Jon LaBadie <j...@jgcomp.com> [20141023 16:59]:
> On Thu, Oct 23, 2014 at 04:28:01PM +1100, Tom Robinson wrote:
> > Now I have to work out why my tape is reporting as smaller! amtapetype
> > reports my tape is only half
> > as big for the same block size...(was 1483868160 is now 743424512). :-/
> >
> > Checking for FSF_AFTER_FILEMARK requirement
> > Applying heuristic check for compression.
> > Wrote random (uncompressible) data at 67415370.8307692 bytes/sec
> > Wrote fixed (compressible) data at 273874944 bytes/sec
> > Compression: enabled
> > Writing one file to fill the volume.
> > Wrote 761266700288 bytes at 57975 kb/sec
> > Got LEOM indication, so drive and kernel together support LEOM
> > Writing smaller files (7612661760 bytes) to determine filemark.
> > device-property "FSF_AFTER_FILEMARK" "false"
> > define tapetype ULT3580-TD5 {
> > comment "Created by amtapetype; compression enabled"
> > length 743424512 kbytes
> > filemark 987 kbytes
> > speed 57975 kps
> > blocksize 512 kbytes
> > }
> > # for this drive and kernel, LEOM is supported; add
> > # device-property "LEOM" "TRUE"
> > # for this device.
> >
> >
>
> Note it is not only reporting the lower size, but dumps
> are experiencing it as well.
>
> IIRC, you are using an LTO-5. My peek at the web says
> that format can record at up to 280Mbps. You are now
> only seeing 58Mbps. Is that a big change from your
> previous runs?
>
> Feeding a drive too slowly, i.e. below its ability to
> stream continuously, can reduce the apparent capacity
> of the tape.
>
> If this is the case you may have to find ways to
> increase the data flow rate to your drive.
>
> Jon
> --
> Jon H. LaBadie j...@jgcomp.com
> 11226 South Shore Rd. (703) 787-0688 (H)
> Reston, VA 20190 (609) 477-8330 (C)
Stepping in, I miss the earlier comments so maybe this is not
appropriate or OT, in which case just toss me in the dust bin.
Your length and speed are way off.
This is my tapetype for a HP Ultrium LTO-5
define tapetype tape-lto5 {
comment "Created by amtapetype; compression disabled"
length 1480900608 kbytes
filemark 3413 kbytes
speed 107063 kps
blocksize 2048 kbytes
part-size 100gb
part-cache-max-size 100gb
part-cache-type disk
part-cache-dir "/holddisk"
}
In this case, amtapetype disappointedly reported only ~100MBs (native
speed per specs is 140MBs) but in my local setup I frequently see
values up to 300MBs with 'averaged xfer rate' around the specs value,
eg, see the attached munin graph of my holdding disk performance from
last night run, the green line is data from the holdding disk to the
tape. LTO-5 will stream from 40MBs (I think) to 150Mbs, lower than
that you're shoe-shinning.
If the data xfer from the holdding disk to the drive can sustain the max
xfer data rate to the drive (140MBs) this suggest you have a dud or
experiencing other hardware issues. I would test the hardware directly
without amanda in the way using native OS tool, dd or whatever you
fancy.
cheers,
jf
--
<° >< Jean-François Malouin
Systems/Network Manager | McConnell Brain Imaging Centre | MNI
3801 University St, Suite WB219, Montreal, QC, H3A 2B4, Canada
