* Abilio Carvalho <abilio.carva...@bbp.ch> [20130430 10:36]:
> sorry, no I hadn't disabled compression. Today I installed mt-st and
> following the wiki I ran:
>
> mt -f /dev/sg2 compression 0
> mt -f /dev/sg2 defcompression 0
>
> but when I now run amtapetype it still tells me:
>
> Applying heuristic check for compression.
> Wrote random (uncompressible) data at 73376008.2580645 bytes/sec
> Wrote fixed (compressible) data at 101095833.6 bytes/sec
> Compression: enabled
>
> how can I make sure hardware compression is off?
Make sure you have a tape loaded.
Replace the tape drive scsi generic device sgX accordingly.
In case of LTO5 here is what I get:
~# tapeinfo -f /dev/sgX
Product Type: Tape Drive
Vendor ID: 'HP '
Product ID: 'Ultrium 5-SCSI '
...
DataCompEnabled: yes
DataCompCapable: yes
DataDeCompEnabled: yes
...
~# mt-st -f /dev/nst0 defcompression 0
~# tapeinfo -f /dev/sgX
...
DataCompEnabled: no
DataCompCapable: yes
DataDeCompEnabled: yes
hth,
jf
>
> On Apr 17, 2013, at 6:40 PM, Jean-Francois Malouin
> <jean-francois.malo...@bic.mni.mcgill.ca> wrote:
>
> > * Abilio Carvalho <abilio.carva...@bbp.ch> [20130417 10:19]:
> >> Well, since noone answered, I had to run amtapetype, so here it is if
> >> anyone else needs it:
> >>
> >> define tapetype LTO6 {
> >> comment "Created by amtapetype; compression enabled"
> >> length 2442818848 kbytes
> >> filemark 1806 kbytes
> >> speed 74006 kps
> >> blocksize 32 kbytes
> >> }
> >
> > Hmmm, speed look way off. Native speed is 160MBs for LTO6...
> > Did you disable hardware compression before running amtapetype?
> > Also, you might want to test with larger blocksize, for LTO5 I use 2MB
> > with good results....
> >
> > hth,
> > jf
> >
> >>
> >>
> >> On Apr 16, 2013, at 3:24 PM, Abilio Carvalho <abilio.carva...@bbp.ch>
> >> wrote:
> >>
> >>> Hi, just a quick question, does anyone have a tape type for an LTO6
> >>> drive? (Ideally an HP Ultrium 6 SCSI)
> >>>
> >>> Thanks
> >>> Abilio
