Im backing up to a network directory thats actually a mount point on a different server.
My backup was slower than usual so i opened up perfmon to have a look.
When selecting the mount point from the Logical Disks section in perfmon i can see that writes/sec & write bytes/sec both show zero for a long period of time, even though the backup percent complete is increasing.
Then all of a sudden the writes to the network share jump massively.
Is there some caching mechanism for backups in sql where during a backup data is only flushed to the disk periodically during backup?