On Tuesday 09 March 2010, rory_f wrote:
>Gene Heskett wrote:
>> On Monday 08 March 2010, rory_f wrote:
>>
>> Please do. It could be something I missed, or it could be a brand new
>> phenomenon to file away in my trivia file.
>
>gene,
>
>ama...@backup tor]$ amtapetype -o -f /dev/nst0 -e 400G
>Writing 1024 Mbyte compresseable data: 31 sec
>Writing 1024 Mbyte uncompresseable data: 31 sec
>Estimated time to write 2 * 409600 Mbyte: 24800 sec = 6 h 53 min
>wrote 12845056 32 Kb blocks in 98 files in 11738 seconds (No space left on
> device) wrote 12910592 32 Kb blocks in 197 files in 11840 seconds (No
> space left on device) define tapetype NEW_IBM_DRIVE {
> comment "just produced by tapetype prog (hardware compression off)"
> length 402432 mbytes
> filemark 0 kbytes
> speed 34955 kps
>}
>
>comparing this tapetype to the last ibm drive (that broke and was replaced
> by this) the speed is nearly half.
>
>define tapetype BROKE_IBM_DRIVE {
> comment "just produced by tapetype prog (hardware compression off)"
> length 402432 mbytes
> filemark 0 kbytes
> speed 71201 kps
>}
>
>This brings me to another question - what could be causing this ?
>
>The system itself has not changed, nor has the cabling, really. unless the
> cables have become damaged (or the scsi card inside the machine is now
> having problems), what else is to check?
If the card is wide scsi, perhaps a cabling issue or termination issue has
caused it to fall back to scsi-II width and speeds? I have read that some
cards do this, and a reboot once the problem is solved, might bring back the
full speed. Might be worth a try just to satisfy the curious cat in all of
us.
>Theoretically, this new drive should be as fast if not faster.. but it
> isn't.
Do you recall the block size used with the previous drive? If it was also
32k which is the default, some speed improvements can be had with larger
block sizes, but I doubt that could make a 2/1 ratio change in the drives
speed.
>At least it seems to *work* now.
Which is nice, but I believe I would take up the speed problem with the
vendor after I had rebooted and checked to see if it persists. Perhaps there
is a spindle speed jumper that is miss-placed on this one? Possibly
automatically interlocked with the write clock speed since you did get the
exact same size, so the drive maintains the same bits per inch.
But I'm making SWAG's here, my knowledge of drives isn't nearly as deeply
ingrained as the scsi experience is.
Perhaps someone else here can help?
--
Cheers, Gene
"There are four boxes to be used in defense of liberty:
soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
The control of the production of wealth is the control of human life itself.
-- Hilaire Belloc
