Fbackup warnings/errors.

[James Hunt]

I'm getting the following 'warnings' in my overnight backup:
fbackup(9999): Interrupted system call
fbackup(2004): WARNING: reader 1: 1st read error, firstread=196608, n=0
fbackup(9999): Interrupted system call
fbackup(2004): WARNING: reader 1: 1st read error, firstread=196608, n=0
fbackup(9999): Interrupted system call
fbackup(2004): WARNING: reader 1: 1st read error, firstread=196608, n=0
fbackup(9999): Interrupted system call
fbackup(2004): WARNING: reader 1: 1st read error, firstread=196608, n=0
fbackup(9999): Interrupted system call
fbackup(2004): WARNING: reader 1: 1st read error, firstread=196608, n=0
fbackup(9999): Interrupted system call
fbackup(2004): WARNING: reader 1: 1st read error, firstread=196608, n=0
fbackup(9999): Interrupted system call
fbackup(2004): WARNING: reader 1: 1st read error, firstread=196608, n=0
fbackup(9999): Interrupted system call
fbackup(2004): WARNING: reader 1: 1st read error, firstread=196608, n=0
fbackup(9999): Interrupted system call
fbackup(2004): WARNING: reader 1: 1st read error, firstread=196608, n=0

This happened for the first time last night and I'm concerned about the integrity of the backup. The backup normally takes 1.5 hours but this time took 4 hours.
It looks to me like it might be a system setting being breached but there's nothing in the syslog or dmesg to indicate this. The disks are on an EMC unit and we've had these checked out too - they've been given the all clear.
We do backup a lot of small files on this system ( not sure how many but 10,000s ) - is there a setting that controls this maybe?

Can anyone out there help/shed some light on what's going on?

TIA.

[Steve Steel]

Hi


9 times out of 10 a bad disc

It cannot read the file on disc to backup

Thus HW check


Steve Steel

[Peter Godron]

James,
have a read of:
http://forums1.itrc.hp.com/service/forums/questionanswer.do?threadId=943856

Sadly no clear solution.
Causes can be disk/memory/tape.
Others have suggested a re-boot.

[Steven E. Protter]

Shalom James,

You are right to be concerned abou thte backup. Its useless.

Some of the files/filesystems scheduled for backup wer not available.

Probably bad disk.

Check with dmesg
xstm or cstm or mstm

SEP

[James Hunt]

Oh dear, doesn't sound good.
As I'm not getting any errors could I put it down to a 'one off'? or, in your experiences, does this error keep occurring?

[Bill Hassell · Accepted solution]

Unfortunately, very few fbackup error numbers were ever documented. Basedd on the text, the term "reader 1" probably referes to one of the several reader processes that fbackup uses to read multiple files in parallel. These reader proceses communicate through shared memory but the message did not indicate what file was being accessed.

As far as a disk error, normally these would be logged in syslog.conf, but just to verify your disks, use dd to read the sectors, something like this:

dd if=/dev/rdsk/whatever of=/dev/null bs=128k

Note the use of rdsk, not dsk, which improves throughput for the dd command. Repeat for each disk on the system. You can also run it for specific lvols (use the rlvol name) but using the raw disks makes for less commands to run. dd will stop with errno 5 (I/O error) if a sector cannot be read.

There is no limit to the number of files that can bed backed up (millions are not a problem), but you can significantly improve fbackup's speed by max'ing the number of reader processes to 6 and adjusting the files per setmark and other values. You should always use a config file with fbackup (-c option). Here is a good example:

blocksperrecord 8192
records 64
checkpointfreq 4096
readerprocesses 6
maxretries 5
retrylimit 5000000
maxvoluses 200
filesperfsm 2000

[James Hunt]

Thanks everyone for all your help and advise.
The following night's backup completed sucessfully and without any of the warning re-appearing. I think that, for now, I'll just keep an eye on it. Should it re-occurr I'll implement some of the fbackup suggestions you've made.

thanks again.