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Re: LTO4 amtapetype problem?
2009-06-12 11:57:16
Jean-Francois Malouin wrote:
Hi,
Not really an Amanda question but I'll try anyway...
I can't get better than ~60MiBs to LTO4 tape when using amtapetype.
I tried 32k 1024k and 2048k, with and without hw compression enabled.
Any hints? I've added some info below. I can provide more upon request.
Note that tapeinfo reports hw compression off but amtapetype says it
on. The changer web interface also tells me that the drive has
hardware compression off too. Puzzling.
Just an off-hand note, and I am not 100% sure it applies specifically to
LTO4, but ...
There was a detailed discussion on the Bacula list last year which
concluded that a tape drive will respect the status of a particular tape
regardless of what your settings are that you have configured the drive
with. So, if you use a tape that was once written with hardware
compression, it will continue to run that way.
Try a brand new tape and see if it behaves any differently.
I'm assuming, of course, that you have also assessed all your hardware
and software and concluded that it ought to be able to support a higher
throughput to the tape.
***
ArcVault-48 with LTO4 Ultrium HP. HBA is a LSI U320 in a PCI-X 133Mhz
slot. Host is a quad core Xeon running Debian/2.6.29.3-i686-64-smp
with amanda-2.6.1p1.
#> tapeinfo -f /dev/sg5
Product Type: Tape Drive
Vendor ID: 'HP '
Product ID: 'Ultrium 4-SCSI '
Revision: 'W23H'
Attached Changer: No
SerialNumber: 'HU18443UTY'
MinBlock:1
MaxBlock:16777215
SCSI ID: 5
SCSI LUN: 0
Ready: yes
BufferedMode: yes
Medium Type: Not Loaded
Density Code: 0x46
BlockSize: 0
DataCompEnabled: no
DataCompCapable: yes
DataDeCompEnabled: yes
CompType: 0x1
DeCompType: 0x1
BOP: yes
Block Position: 0
#> ~amanda/sbin/amtapetype -f -b 1024k /dev/nst1
Applying heuristic check for compression.
Wrote random (uncompressible) data at 60250145.5737705 bytes/sec
Wrote fixed (compressible) data at 73505177.6 bytes/sec
Compression: enabled
Writing one file to fill the volume.
Wrote 813618429952 bytes at 62054 kb/sec
Writing smaller files (8135901184 bytes) to determine filemark.
define tapetype unknown-tapetype {
comment "Created by amtapetype; compression enabled"
length 794549248 kbytes
filemark 1996 kbytes
speed 62054 kps
blocksize 1024 kbytes
}
regards,
jf
--
---------------
Chris Hoogendyk
-
O__ ---- Systems Administrator
c/ /'_ --- Biology & Geology Departments
(*) \(*) -- 140 Morrill Science Center
~~~~~~~~~~ - University of Massachusetts, Amherst
<hoogendyk AT bio.umass DOT edu>
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Erdös 4
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