Speeding dump times - data segments affect speed?

[unknown]

We've been performance testing.

The database dumps of db1 (87 GB data) take 16 minutes at
5.4 GB/min.

The database dumps of db2 (16 GB data) take 11 minutes at
1.6 GB/min.

The database dumps of db3 (47 GB data) take 8 minutes at 5.8
GB/min.

By ratio of data size, I would expect db2 to dump in 3 mins.

I've tried more stripes without success. I'm wondering if
the number of data segments might be the issue ... db1 has
45, db2 has only 6 with a range of sizes, db3 has 8 with
large sizes.

Is this the wrong track? Any other suggestions?

[A. M.]

Post by unknown
We've been performance testing.
The database dumps of db1 (87 GB data) take 16 minutes at
5.4 GB/min.
The database dumps of db2 (16 GB data) take 11 minutes at
1.6 GB/min.
The database dumps of db3 (47 GB data) take 8 minutes at 5.8
GB/min.
By ratio of data size, I would expect db2 to dump in 3 mins.
I've tried more stripes without success. I'm wondering if
the number of data segments might be the issue ... db1 has
45, db2 has only 6 with a range of sizes, db3 has 8 with
large sizes.
Is this the wrong track? Any other suggestions?

The mostly like case is that it depends on the speed
of your disks and your dump device(s).

How are the 3 databases set up on their devices? What
are the disk devices? What is the dump target?

-am © 2007

[Michael Peppler]

Post by A. M.

Post by unknown
We've been performance testing.
The database dumps of db1 (87 GB data) take 16 minutes at
5.4 GB/min.
The database dumps of db2 (16 GB data) take 11 minutes at
1.6 GB/min.
The database dumps of db3 (47 GB data) take 8 minutes at 5.8
GB/min.
By ratio of data size, I would expect db2 to dump in 3 mins.
I've tried more stripes without success. I'm wondering if
the number of data segments might be the issue ... db1 has
45, db2 has only 6 with a range of sizes, db3 has 8 with
large sizes.
Is this the wrong track? Any other suggestions?

The mostly like case is that it depends on the speed
of your disks and your dump device(s).
How are the 3 databases set up on their devices? What
are the disk devices? What is the dump target?

Also - is the 87 GB database actually full, or is it just the size of the
devices ?

Michael

[unknown]

Thanks for your response.

87GB is the actual data dumped:
Sep 11 20:48:46 2007: Backup Server: 4.58.1.1: Database db1:
92858194 kilobytes DUMPed.

db1 is
* 113 GB total size (103 GB data, 10 GB log)
* It is spread across 18 database devices and 2 log devices
in a non-striped mirrored environment

db2 is
* 32G GB total size (26 GB data, 6 GB log)
* It is spread across 5 database devices and 3 log devices
in a non-striped mirrored environment

Both of these databases are dumping to the same location.
db2 shares all of it's devices with db1

Post by A. M.

Post by unknown
We've been performance testing.
The database dumps of db1 (87 GB data) take 16 minutes

at >> 5.4 GB/min.

Post by A. M.

Post by unknown
The database dumps of db2 (16 GB data) take 11 minutes

at >> 1.6 GB/min.

Post by A. M.

Post by unknown
The database dumps of db3 (47 GB data) take 8 minutes

at 5.8 >> GB/min.

Post by A. M.

Post by unknown
By ratio of data size, I would expect db2 to dump in 3

mins. >>

Post by A. M.

Post by unknown
I've tried more stripes without success. I'm wondering

if >> the number of data segments might be the issue ...
db1 has >> 45, db2 has only 6 with a range of sizes, db3
has 8 with >> large sizes.

Post by A. M.

Post by unknown
Is this the wrong track? Any other suggestions?

The mostly like case is that it depends on the speed
of your disks and your dump device(s).
How are the 3 databases set up on their devices?
What are the disk devices? What is the dump target?

Also - is the 87 GB database actually full, or is it just
the size of the devices ?
Michael
--
Michael Peppler - Peppler
http://www.peppler.org Sybase DBA/Developer -
TeamSybase: http://www.teamsybase.com Sybase on Linux FAQ
- http://www.peppler.org/FAQ/linux.html

[A. M.]

Post by unknown
Thanks for your response.
92858194 kilobytes DUMPed.
db1 is
* 113 GB total size (103 GB data, 10 GB log)
* It is spread across 18 database devices and 2 log devices
in a non-striped mirrored environment
db2 is
* 32G GB total size (26 GB data, 6 GB log)
* It is spread across 5 database devices and 3 log devices
in a non-striped mirrored environment

OK, here's one problem. For those sizes, you should
really be using striped devices. Look at setting up
RAID1+0 with a stripe size no larger than the track
width. The size should be some multiple of your
page/extent size. You don't say what version of ASE
you are using but that had large device support as
far back as version 11.5. So try using fewer but
larger segments. These should not conflict on your
physical disks as well, so pay attention to your
device layouts.

Post by unknown
Both of these databases are dumping to the same location.

Is that at the same time? Is the target location on
the same physical disks? If so, move it. Its a
bottleneck doing it like that.

The dump devices should also be striped.

Post by unknown
db2 shares all of it's devices with db1

OK, you should split that up to minimise contention.
You also mentioned a third db in your original post.
Anything interesting happening with it? I noticed
its dump speed was the fastest. Compare its layouts
to these two.

Also what type of disks/storage do you have? SCSI or
FibreChannel? And what's their rated speed?

-am © 2007