| T.R | Title | User | Personal
Name | Date | Lines |
|---|
| 3709.1 | | DECWET::KOWALSKI | Time's not for saving | Tue Apr 01 1997 22:12 | 15 |
| Throwing out the first pitch, hopefully not a
wild one, my guess the software is the bottleneck
and the performance is unreasonable.
They're achieving .42 MB/s throughput from disk to tape.
EISA bus on a 2000 is rated 33MB/s maximum. The TX88
is rated 2.5 MB/s maximum. Assuming there are no issues
with getting the data off disk and into the I/O stream,
a 2100 should be able to make a TZ88 stream at full
speed. The only other issue I could see would be
contention on the internal SCSI bus between I/O to the
tape and system activities such as paging. They could
move the drive to a separate SCSI controller to see
if that helps. If it doesn't, the software would seem
to be the likely suspect.
|
| 3709.2 | | DECWET::KOWALSKI | Time's not for saving | Tue Apr 01 1997 22:14 | 4 |
| Remember, Seagate delivers PC backup software,
not enterprise level software. :^) Microsoft
doesn't use NT backup internally for its
enterprise systems. They use NetWorker.
|
| 3709.3 | | WARFUT::MELLING | | Wed Apr 02 1997 03:44 | 16 |
|
I notice from note 6238.1 on the ask_ssag conference a note
was posted relating to a throughput of 0.46Mb per second to
a TZ875 on BACKUP EXEC.
The tape unit is on the same bus as the boot disk,during backup
there seemed to be no activity to the boot disk.At the time of
backup there were no users on the system
Perhaps this is the default throughput rate for NT BACKUP and
BACKUP EXEC.
I would have thought there may be some spec figures as this is
likely to be a frequently visited topic.
regards
tony
|
| 3709.4 | We do a little better | KEIKI::WHITE | | Wed Apr 02 1997 09:45 | 7 |
|
AS2000 4/233 TZ87 on private KZPAA disks on Internal NCRC810
and KZPAA using Striping with parity on three disk RAID set.
We backed up 3 gigabytes in 40 minutes using NT 3.51.
Bill
|
| 3709.5 | | DECWET::KOWALSKI | Time's not for saving | Wed Apr 02 1997 21:57 | 8 |
| So, is the paging file on the boot disk? Is the boot disk
at a higher priority SCSI id than the tape? Since .4 got
3x better performance, there must be some fixable
block hanging around. It's not time yet to say, "ya
gets what ya pays for".
You might want to revisit the assumption that getting the
data from its storage to memory is not limiting.
|
| 3709.6 | | WARFUT::MELLING | | Thu Apr 03 1997 04:52 | 24 |
|
Hello,
Thanks to .4 for the input indicating that the tape unit
should be capable of performing to spec of 1.25 Mb /sec.
I have not yet been back to the customer's site,today I
built an NT V3.51 system onto an AS2100 and checked out
throughput from a partition on the boot disk and also
from a JBOD on an EISA based SWXCR.
The figures for 84Mb backup and verify were approx 1 Mb/sec
to a TZ87 using NT BACKUP.
I intend to put service pack 4 on tomorrow along with a
TZ88 to see how it performs.
The data is a copy of two directories from the NT release cd
and hopefully I should then be able to reproduce the test
at the customer site.
regards
tony
|
| 3709.7 | | WARFUT::MELLING | | Sat Apr 12 1997 01:07 | 12 |
|
I have re run the tests now on the customer system and get similar
results to that which the customer gets for normal operation.
The verify though seems to take a lot longer than backup,something
in the order of 3 x backup time
I have run the test on a TLZ07 and this allows backup and verify
at approx 0.36 Mb /sec and both operations take the same length of
time
tony melling
|