Tuesday, May 24, 2011


Normally this wait type can be seen in backup and restore transactions.and whenever you will see this wait type your backup/restore process will be in suspended state most of the time because the process is waiting to get IO resource to proceed its operation and it will wait till certain time period then moved in suspended state. In that case your process will take more than its usual time to complete or most of the time it will hung or will showing in executing state for unknown time duration.

This wait type occurs when a task is waiting for asynchronous I/Os to finish. This wait type is normally seen with few other wait types like BACKUPBUFFER,BUCKIO etc. This is clear indication of DISK IO issue.You can also get the Average disk queue length or current disk queue length value at the same time when you are getting this wait type.Compare both counters and if these counters have high value then you should look into your storage subsystem. Identify disk bottlenecks, by using Perfmon Counters, Profiler, sys.dm_io_virtual_file_stats and SHOWPLAN.
Any of the following reduces these waits:
1.      Adding additional IO bandwidth.
2.      Balancing IO across other drives.
3.      Reducing IO with appropriate indexing.
4.     Check for bad query plans.
5.     Check for memory pressure

 We can also corelate this wait type between Memory pressure and Disk IO subsystem issues.

Friday, May 6, 2011


Today I was working on an issue in which backup job was showing in executing state since last 2 days.Initially my observation was either it was hung in middle of its process or it was processing very slow.Here i decided to see the lock wait type for this process.when i gather this info i see the wait type was BACKUPBUFFER wait type.

BACKUPBUFFER Wait Type:-This wait type Occurs when a backup task is waiting for data, or is waiting for a buffer in which to store data. This type is not typical, except when a task is waiting for a tape mount. This wait stats will occur when you are taking the backup on the tape or any other extremely slow backup system.This wait type can be seen with one more wait type i.e. ASYNC_IO_COMPLETION. 

These both wait type indicates that the issue is with storage/disk subsystem.So solution is to either ask your storage team to look in this or change your disk/storage subsystem and run your backup on a healthy and fast storage subsystem.