[Info-vax] RX2800 sporadic disk I/O slowdowns

[Volker Halle]

Am 05.11.2024 um 20:51 schrieb Richard Jordan:
> On 11/5/24 10:32 AM, Volker Halle wrote:
>> Am 18.10.2024 um 20:26 schrieb Richard Jordan:
>...
>       I have monitor running and have been checking the I/O rates and 
> queue lengths during the 30+ minute runs and the multi-hour runs, and 
> the only diffs there are the overall I/O rates to the two disks are much 
> lower on the long runs than on the normal short ones.

Rich,

did you consider running some disk-IO benchmarking tool ? On the two 
disks sometimes affected by the problem ? And on other disks on this 
RAID controller ?

This could provide some baseline achievable I/O rates and response 
times. You could then run those test while 'the problem' exists and 
during the 'short runs'.

If you also see the problem with a standard disk-IO benchmark, 
considerations about local/global buffers may be less important.

There is the DISKBLOCK tool on the Freeware CDs, but I also have a more 
current version on: https://eisner.decuserve.org/~halle/#diskblock

DISKBLOCK has a 'TEST' command to performance disk performance testing 
(read-only and/or read-write).

Volker.