| Title: | MAGNETIC TAPEDRIVES |
| Moderator: | STKHLM::GJOHNSSON |
| Created: | Mon Sep 21 1987 |
| Last Modified: | Fri Jun 06 1997 |
| Last Successful Update: | Fri Jun 06 1997 |
| Number of topics: | 3775 |
| Total number of notes: | 13147 |
Hello,
I have a customer who has purchased a TZ87-DA to effect backups
on an LAVc.
The unit has been connected to a V4VLC and backups run from it,the
time taken to backup disks on the cluster varies :
14 hours for approx 2 gb on an rz29
4 hours for approx 1 gb on an rz28
I have requested that the customer looks at the Backup account
quotas and to backup/restore those disks taking a long time to
backup.
The customer is to move the tz87 to a V4000-90 instead on the
V4VLC.
The customer also noticed that during the backup procedure,approx
12 gb of data to be saved that the procedure requested a second
tape after approx 5 gb had been saved.
The customer is running VAX VMS V6.1 on their cluster.
Is there anything that can be set up to reduce the time taken
other than the above.
regards
tony melling
Warrington U.K.
| T.R | Title | User | Personal Name | Date | Lines |
|---|---|---|---|---|---|
| 3682.1 | COOKIE::FROEHLIN | Let's RAID the Internet! | Fri Feb 28 1997 00:32 | 23 | |
> 14 hours for approx 2 gb on an rz29
That's ~40 kB/s...sure can do better.
They should use a DIOLM=FILLM=30-50 and a /BLOCKSIZ=65024.
What kind of SCSI controller is the tape connected to?
How is the disk accessed (local or served via Ethernet)?
Is the disk connected to the same SCSI bus as the tape?
What's a V4VLC?
To check whether or not it's the tape they should do this
comparison test:
$ BACKUP/... InputDisk: NLA0:a.a/SAVE
This gives a good idea about how long it takes to get the data off the
disk. Sometimes slow backup times are caused by slow disk access.
Guenther
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