nowaitio on hp-ux

[Thomas Greig]

have installed a new disk-system with 512mb cache and got the suggestion to create the filesystems with "nowaitio".

Does anyone have any experience with this? and what is the "equievelent" of nowaitio on HP-UX?

[Thomas Greig]

abit more info of the system we have:
hp-ux 11i v1. on a 9000/800/rp3440.
with a ATABOY disk-system

[Florian Heigl (new acc) · Accepted solution]

I think there's two settings that would influence this,

the FS_ASYNC=1 kernel tunable, and
the utility scsictl with the immediate_report option set to '1' (this should be done via an rc script, as it is a volatile setting.

[Jon M Zellhoefer]

For mounted filesystems, edit the fstab to include the following 3 options for the filesystems that you want nowaitio on ...

mincache=direct,convosync=direct,nolog

it will force the I/O directly to the cache enabled array - it will not wait for confirmation that the I/O has been offloaded from cache to disk.

Jon

[Thomas Greig]

thanx for the replies.
the "mincache=direct,convosync=direct,nolog" is aparently only supported in OnlineJFS products, but I changed the fs_async from 0 to 1 and this gave me much better times in moving data (earlier : 45sec per GB to copy from a Vol.Group to another, now: 36sec per GB).

cheers
Thomas Greig