fbackup very slow when Oracle instances open

[Michael O'brien_1]

Hi,

I have noticed when I try and run an fbackup job when an couple of oracle instances are open fbackup take forever. I'm not backing up the open Oracle instances. If I then run the backup job when all of the instances are closed down, it takes a fraction of the time.

Does anyone know a way of speeding up the fbackup job. When I look at the process through glance the Oracle process seem to take up the top processes. I've tried to change the settings in the fbackup_config file but it doesn't seem to make much difference.

Any suggestions would be much appriciated. I'm using a LTO tape drive.

Thanks
Mike

[Steven E. Protter]

fbackup will NOT back up oracle instances while they are open. It will copy the files, but they will be USELESS for a restore.

You either need another tool, or you need to shut down those databases.

SEP

[T G Manikandan]

When the backup is done after the database is shutdown it is a clean or closed backup.

If you are performing backup while the database is running (HOT backup)then you should place the tablespaces in hot backup mode before the backup.

Without both the above,the backup will not be useful for restoration.

RMAN from Oracle is a wonderful utility for backup and restore.

[twang]

Take a look at the disk io during the fbackup and oracle running:
# iostat 5 50
It may be caused by IO intense opertaions on a same disk.

[T G Manikandan]

Also,I find good backup speed on machines with more memory,more performance.
One of the reasons could be that the database processes are utilizing most of the resources that makes fbackup take too long to finish the process.

Revert on the machine configuration..Amount of memory and its usage!

[Thierry Poels_1]

Hi,

there is another possible reason:
fbackup will restart the backup of a file if it detects that the file has been changed during the backup. So if your database is running, fbackup might backup each datafile a couple of times.
Check your logfile for "file in use" messages.

As already mentioned: fbackup is not the most ideal tool to backup running databases.

regards,
Thierry Poels.

[Michael O'brien_1]

Thanks for your replies, I'm not backing up the active Oracle instances. The partitions I'm backing up are on an external storage (HW path 0/2/0/0) and the tape devices is connect via the on onboard scsi port, HW PATH 0/0/1/0.

I think the issue is with fbackup and the LTO tape device. I was considering changing the process prioity of the fbackup command?
Any suggestions

Thanks
Mike

[RolandH]

Hi Mike,


i think that is deffinatly a problem of open files. fbackup will not backup them. See the man page of fbackup for the option "-c" config file. Here you can set several parmaters that can speed up your backup. Play a bit with higher or lower values. May be maxretries is one paramater that can be set to 1 if you backup with a running database. If you backup with a closed database use maxretries with a value of 3, perhaps. That is only a suggestion. Some parameters are dependent what you backup. A lot of small or big files. So it is like it is- you must play with that options. But every backup is useless if you not test your recovery procedure. That are my 2 cent to that.

HTH
Roland

[Michael O'brien_1]

Hi Roland,

I've change the fbackup_config file with the following settings

blocksperrecord 128
records 64
checkpointfreq 128
readerprocesses 6
maxretries 2
retrylimit 5000000
maxvoluses 100
filesperfsm 200

I've started a backup at 10:49 GMT, I'm backing up 22gb. The server is an N-Class with 6GB memory, 10GB swap and 4 CPU's.

The server currently has 7 active oracle instances. The files being backed up are on the same partition as one of the oracle instances, but the files don't belong to the active oracle instance.

I'll post the finish time when the backup completes.

Thanks for your suggestions.
Mike

[Thierry Poels_1]

hi,

what is the load of the relevant disks? Backup is IO-bound, not cpu-bound.

and how about some more fbackup tuning:

blocksperrecord 256
checkpointfreq 1024
filesperfsm 2000

good luck,
Thierry.

[Michael O'brien_1]

Hi Thierry,

The output of the iostat I guess shows I have an IO bottleneck. The partition on the I'm backing up is on the c6t14d0 disk.

device bps sps msps

c1t6d0 6 1.6 1.0
c2t6d0 0 0.0 1.0
c4t10d0 186 22.2 1.0
c4t10d2 44 4.6 1.0
c6t12d0 5 0.6 1.0
c6t14d0 5677 155.1 1.0
c6t8d0 6 0.8 1.0
c4t10d4 0 0.0 1.0


I will try the next backup with the new settings in the fbackup_config.

Thanks
Mike

[RolandH · Accepted solution]

Another suggestion !!

Check you disk activity with "sar -d 5 100"
if you have running databases and stopped databases (if fbackup isn't run) You said that the data you backup is on the same volume as the databases. So perhaps it is also a IO problem of your disks.

HTH
Roland

[RolandH]

Thierry & Mike,


the value from the blocksperrecord is dependent from the tape. The tape must support such a value. So check that first. You can not !!! take every value what you want. For beginning 128 is ok. Test it first with that value.

Roland

[Michael O'brien_1]

The backup completed, I guess just over 2 hours for 22gb isn't too bad. I didn't create an imdex file and used the revised fbackup_config file. I'll try another backup too include new settings and see how fast the backup is. When I ran the bakup yesterday with the old fbackup settings and an idex file it hadn't complete 10 hours later.

Thanks for all your suggestions and help.
Cheers
Mike

[RolandH]

Hi Michael,


nice to hear your problem seems to be solved. =|:-}
But spent also the others point, who has taken time to solve your problem.

Roland
(No points for that, please)