Morten Torstensen wrote:
> Err... are you sure you want to turn on write-caching? You will have
> filesystem corruption in case of a power-down, panic or other crashes
> then. It does help to have a battery backup on the 3ware card, assuming
> it is smart enough to write the changes to disk before the OS starts.
Yea, I'm sure. With write-caching turned off on the 3Ware controller only and
writing to an XFS filesystem:
------Sequential Output------ --Sequential Input- --Random-
-Per Chr- --Block-- -Rewrite- -Per Chr- --Block-- --Seeks--
Machine Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP /sec %CP
Beryl 5G:64k 9968 15 10447 1 3924 0 25071 38 201973 18 542.5 3
------Sequential Create------ --------Random Create--------
-Create-- --Read--- -Delete-- -Create-- --Read--- -Delete--
files:max:min /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP
Beryl 16 253 1 +++++ +++ 230 1 225 1 +++++ +++ 149 1
Block writes drop to 10MB/Sec plus the system becomes non-responsive during
large writes. Can anyone tell me this is acceptable? I'm really at a loss when
you and Feizhou tell me to turn off write-caching. How do you get anything
even approaching *tolerable* performance?