PATROL detected 0.0% write cache hit ratio

[P Arumugavel]

Hi Admins,

Please help in alert mentioned in subject lane.

These are alerts I used to get on daily.

OS Info: HP-UX 11.31

Please suggest for the solution. Thanks in advance.

Rgds...

[Bill Hassell]

There is nothing wrong. The write cache percentage indicates the amount of data that is written over and over again. In other words, if your programs write a record, then write the same (unchanged) record again, the write cache will be used as the source for the I/O. SInce this is not very common, the percentage is very small. If you write an entire file, the write cache will contain many of the records. But it won't be used again unless you write the same data to the same or another file.

Fix the messages by configuring Patrol to not monitor write cache percentage.

[P Arumugavel]

Thanks for the rapid reply.

#sar -b 2 5

HP-UX hostname B.11.31 U 9000/800    07/05/11

13:19:12 bread/s lread/s %rcache bwrit/s lwrit/s %wcache pread/s pwrit/s
13:19:14       0     201     100       1      10      85       0       0
13:19:16       0     205     100       3      18      81       0       0
13:19:18       0     452     100      10      13      20       0       0
13:19:20       0     314     100     144      23       0       0       0
13:19:22       0     586     100       4     168      98       0       0

Average        0     351     100      33      46      30       0       0

But sometime the write cache goes up 80+

please explain. I didn't get you.

Rgds...

[Steven E. Protter]

Shalom,

This performance collection script may be of assistance for you.

System Performance

Some assembly required.

SEP