Backup Failing, plenty of disk space

[UOFMOO]

Good morning,

We get frequent (1 out of 3) "sqlmaint.exe failed" errors during backups for one of our larger databases (40GB). So i removed the maintenance plan and put in a custom backup job to get a better error msg in the log:

BackupMedium::ReportIoError: write failure on backup device 'F:\MSSQL\mydb_2008_1_3_21_45.BAK'. Operating system error 112(There is not enough space on the disk.).

However, we have PLENTY of space on disk:
LOG DISK - NTFS - used space = 2GB, free space = 81GB
BACKUP DISK - NTFS - used space = 29GB, free space = 82GB
So even if it doubled in size, there would still be 50GB free.

Any ideas?
Thanks!!

[skhanal]

Is 40GB total for both data and log files?

If database size is 40 GB and you have 82 GB free, then it is possible that the disk may have gone bad. Did you see any disk errors in windows system event log?

[UOFMOO]

Hello, yes 40GB is both data and log size in total.

I wondered if the disk is bad, but didn't see any errors in the windows system log or application log corresponding to the problem. There was one security policy that got applied just before my backup that failed, but i am not certain what that policy was, or if it could prompt an error to indicate it's out of disk space?

For now I adjusted the backup times to run one hour earlier and triple checked that there is only one backup running at a time. There does not seem to be any interference.

Has anyone else seen this? Interestingly, it failed regularly (almost daily) with the maintenance plan, but only once so far (in a month) with the "BACKUP DATABASE" command job i wrote. Up until this failure I just assumed the failures had to do with SQL Server maintenance plans.

[rmiao]

Is f:\ backup disk you mentioned? How many days of backup file do you keep on the disk? Did you set disk quote?

[skhanal]

With maintenance plan, older backups are deleted after completing the new backup, so at any time you need space based on the number of days backup maintenance plan is keeping plus one (for current backup)

[UOFMOO]

Hi All,
this continues to be a problem...
we only keep one backup at any time on disk.

for now we have set the backup folder to un-compressed, and are now deleting the previous backup before doing a full backup (before we would only delete it after the full backup was successful). it works, but i'm not content with the solution...

Thanks all.

[rmiao]

Did you check with win admin to see if there is disk quote? It'll limit amount of space be used for an account even disk has plenty free space.