I wrote (in part):
We're seeing some odd behavior on an AlphaStation 255/233 running DU 4.0B.
There are 6 external 4GB drives in a StorageWorks cabinet attached to the
machine via a KZPSA (firmware version: DEC P01 A10). The machine
recognizes the disks just fine, they fsck, and they're mounted at boot time
normally.
However, it appears that the first time a disk on this chain is accessed
after reboot (or perhaps even after some time has passed) there's a quite
noticeable delay - even doing an "ls" on an empty partition on one of the
disks takes ~15 seconds.
Many thanks to
David Buxton
Knut Hellebo
Sean O'Connell
Alan Rollow
Donald Rye
who all pointed out that there's a "feature" in DU 4.0 which, if enabled,
spins down idle disks to save power. One can control this behavior from
the GUI "dxpower" or from the command line via sysconfig ("sysconfig -q pwrmgr"
will show the settings as currently configured). The whole thing is a
kernel option, so it's easy enough to just take it out.
The defaults set on my machine (which must have come from the factory this
way, since I've never conciously turned it on) were that the power saving
stuff was on and the idle spindown time was 20 minutes. It's all
documented in the DU 4.0 sysadmin manual (AA-PS2RE-TE, Chapter 4).
Pat Wilson
paw_at_dartmouth.edu
Received on Thu Sep 25 1997 - 15:02:21 NZST