How often does Samba write to disk?

[TJ_22]

samba-3.0.7-1.3E.1

Does anyone know how often samba sync's itself with the disk?

[Steven E. Protter]

Any time Samba has to write it tries. That means when it has write requests.

There are several factors that can delay writes, which include system wait i/o as in other write requests inline ahead of Samba.

SEP

[TJ_22]

what about the "sync always" command which causes Samba to flush every write to disk? What happens when this isn't on? Is it held in a cache and then wrtiien to disk every so often?

Thanks,

T.J.

[Gopi Sekar]

sync always ensures that samba writes the data to the disk before every write request gets completed.

otherwise in general, any application which wants to write data to hard disk simply gives the data to the kernel and the linux kernel will decide apprpriate time (based on CPU idle time, hard disk I/O performance, cache buffer) to write the data actually in to the disk.

enabling sync always has its own advantage and disadvantage:

adv: your data is always written to the hard disk, incase of powerfailure and machine goes down abruptly also your last second data is written to the hard disk.

dis-adv: server response goes very badly because it has to write the data back to the disk (which is very much slower than the CPU) every time and until the data is written the server will not respond back to the client.

Hope this helps,
Gopi