Performance issue Tru64 LTO3 versus SDLT

[Uwe Zessin]

SN-KZPCA-AA:
Single Channel LSI SYM 8952U
Ultra-2 LVD (=80 MegaBytes/second)

[wendling]

What SCSI controller would you recommand for tha LTO (tru64 5.1b patch kit 6)?

[Uwe Zessin]

You could try the 3X-KZPEA-DB, which is a 2-channel Ultra-3 adapter:
http://h18002.www1.hp.com/alphaserver/products/storage/kzpea/index.html

are you sure you are limited by the bus bandwidth? I've looked through this thread, but I don't have seen whether you have mentioned your current throughput.

The SDLT320 does max. 16 MegaBytes/second native (uncompressed) which is below the _minimum speed_ of an LTO-3 tape drive: 20-35 MB/s native.

Depending on the Model, LTO-3 tape drives can do 60-80 MegaBytes native. If the system cannot feed enough data to the tape drives it goes into start/stop mode (called 'shoe-shining' - which is slow, damages the media and the tape drive long-term).

[wendling]

here are some test results:
(tape0 ist lto3 and tape1 is sdlt320)
# time /sbin/vdump -0 -f /dev/tape/tape0_d1 /data3
path : /data3
dev/fset : /dev/disk/dsk2d
type : ufs
vdump: Date of last level 0 dump: the start of the epoch
vdump: Dumping directories
vdump: Dumping 22973779405 bytes, 34 directories, 411 files
vdump: Dumping regular files
vdump: Status at Wed Jan 14 11:46:51 2009
vdump: Dumped 17607250649 of 22973779405 bytes; 76.6% completed
vdump: Dumped 18 of 34 directories; 52.9% completed
vdump: Dumped 42 of 411 files; 10.2% completed
vdump: Rewinding and unloading tape
vdump: Status at Wed Jan 14 11:49:55 2009
vdump: Dumped 22973779405 of 22973779405 bytes; 100.0% completed
vdump: Dumped 34 of 34 directories; 100.0% completed
vdump: Dumped 411 of 411 files; 100.0% completed
vdump: Dump completed at Wed Jan 14 11:49:55 2009
real 8m16.55s
user 0m39.15s
sys 1m13.21s
# time /sbin/vdump -0 -f /dev/tape/tape1_d1 /data3
path : /data3
dev/fset : /dev/disk/dsk2d
type : ufs
vdump: Date of last level 0 dump: the start of the epoch
vdump: Dumping directories
vdump: Dumping 22973779405 bytes, 34 directories, 411 files
vdump: Dumping regular files
vdump: Status at Wed Jan 14 11:56:21 2009
vdump: Dumped 17607250649 of 22973779405 bytes; 76.6% completed
vdump: Dumped 18 of 34 directories; 52.9% completed
vdump: Dumped 42 of 411 files; 10.2% completed
vdump: Rewinding and unloading tape
vdump: Status at Wed Jan 14 11:59:18 2009
vdump: Dumped 22973779405 of 22973779405 bytes; 100.0% completed
vdump: Dumped 34 of 34 directories; 100.0% completed
vdump: Dumped 411 of 411 files; 100.0% completed
vdump: Dump completed at Wed Jan 14 11:59:18 2009
real 8m30.46s
user 0m42.88s
sys 1m24.30s
# time /sbin/vdump -0 -U -f /dev/tape/tape0 /data3
path : /data3
dev/fset : /dev/disk/dsk2d
type : ufs
vdump: Date of last level 0 dump: the start of the epoch
vdump: Dumping directories
vdump: Dumping 22973779405 bytes, 34 directories, 411 files
vdump: Dumping regular files
22973
vdump: Status at Wed Jan 14 14:00:46 2009
vdump: Dumped 17607250649 of 22973779405 bytes; 76.6% completed
vdump: Dumped 18 of 34 directories; 52.9% completed
vdump: Dumped 42 of 411 files; 10.2% completed
vdump: Rewinding tape
vdump: Status at Wed Jan 14 14:03:09 2009
vdump: Dumped 22973779405 of 22973779405 bytes; 100.0% completed
vdump: Dumped 34 of 34 directories; 100.0% completed
vdump: Dumped 411 of 411 files; 100.0% completed
Page 1
Sans titre
vdump: Dump completed at Wed Jan 14 14:03:09 2009
real 7m45.33s
user 0m37.95s
sys 0m58.56s
# time /sbin/vdump -0 -U -f /dev/tape/tape1 /data3
path : /data3
dev/fset : /dev/disk/dsk2d
type : ufs
vdump: Date of last level 0 dump: the start of the epoch
vdump: Dumping directories
vdump: Dumping 22973779405 bytes, 34 directories, 411 files
vdump: Dumping regular files
vdump: Status at Wed Jan 14 13:03:39 2009
vdump: Dumped 6146282201 of 22973779405 bytes; 26.8% completed
vdump: Dumped 18 of 34 directories; 52.9% completed
vdump: Dumped 40 of 411 files; 9.7% completed
vdump: Status at Wed Jan 14 13:09:56 2009
vdump: Dumped 12542612185 of 22973779405 bytes; 54.6% completed
vdump: Dumped 18 of 34 directories; 52.9% completed
vdump: Dumped 41 of 411 files; 10.0% completed
vdump: Status at Wed Jan 14 13:20:08 2009
vdump: Dumped 22949761753 of 22973779405 bytes; 99.9% completed
vdump: Dumped 18 of 34 directories; 52.9% completed
vdump: Dumped 43 of 411 files; 10.5% completed
vdump: Rewinding tape
vdump: Status at Wed Jan 14 13:20:50 2009
vdump: Dumped 22973779405 of 22973779405 bytes; 100.0% completed
vdump: Dumped 34 of 34 directories; 100.0% completed
vdump: Dumped 411 of 411 files; 100.0% completed
vdump: Dump completed at Wed Jan 14 13:20:50 2009
real 23m22.53s
user 0m43.13s
sys 1m9.80s

[Pontier]

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Cordialement.