I am going to contact my CE so that he can come and take a serious look at
this. I had realized that performance was poor, but not really how poor
until I ran that command. We had trouble with the SCSI adapter once before,
so he can take another look at that. These 6 tape drives are all we have
attached to this system, but I will have him check the items you mentioned
below. Thanks for all your help!
-----Original Message-----
From: Richard Sims [mailto:[EMAIL PROTECTED]]
Sent: Friday, April 20, 2001 4:01 PM
To: [EMAIL PROTECTED]
Subject: Re: LTO performance
>timex dd if=/dev/zero of=/dev/rmt1 bs=1024 count=1000
>
>The result was real 21.06 seconds. This falls way short of what I would
>expect when the advertised sustained transfer rate is supposed to be
>15MB/sec native (30MB/sec compressed). ...
Debbie - That indeed sounds poor. As Nathan suggested, look into the
microcode level. Also make sure you have a recent/latest
device driver level in the 3466.
I also wonder about the SCSI (assuming that's the 3583 attachment method).
Look for errors in the AIX Error Log. Use SMIT to check the 3466's
SCSI adapter for having correct settings. If there is a Host Interface
Board in the 358x, check for it being in the correct mode (LVD/HVD) to
match the SCSI adapter in the AIX system. Assure that the drive is
terminated, SCSI-wise, and that the correct type of terminator is used.
I presume that the 358x units are the only things on the SCSI chain,
which is to say no mongrel stuff to cause the SCSI bus speed to be
dropped to a low common denominator, and nothing to
generate SCSI noise on the bus.
Something is definitely misconfigured there. Given that it's a 3466,
perhaps IBM should be doing the analysis to find out what's wrong.
Richard Sims, BU
