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 [email protected]
11226 South Shore Rd. (703) 787-0688 (H)
Reston, VA 20190 (609) 477-8330 (C)
