On Sun, 4 Sep 2011, Benny Lofgren wrote:
On 2011-09-04 07.39, David Vasek wrote:
No, Marco, it is not true. There is a difference between unloading the
heads in a controlled way and by an emergency retract. Doing emergency
retract repeatedly is not good, really.
That used to be true in the dark ages, when disk drives were as large as
washing machines and the actual disk packs were removable and 14" in
diameter. But in this day and age, what Marco says is entirely correct.
No. What Marco says was correct in 90's and early 2000's when disks
employed CSS (Contact Start-Stop) mechanism. In recent years all laptop
drives and almost all desktop and "server" drives (with exception of some
lower end Seagates) use parking on a ramp.
This is the docs for the drive Steve (the OP) has in his Acer laptop.
Please look at the chapter 6.3 (pages 29, 30).
http://www.hgst.com/tech/techlib.nsf/techdocs/1F70FDFFB4DE1EBB86257538007E4CFE/$file/TS5K500.B_OEM_Specification_R18.pdf
The same is true for other modern Hitachi drives and for drives from other
vendors probably too, but they do not provide any useful documentation for
their drives.
There is some more detailed description of ramp parking:
http://www.hgst.com/tech/techlib.nsf/techdocs/9076679E3EE4003E86256FAB005825FB/$file/LoadUnload_white_paper_FINAL.pdf
Regards,
David
The OP can safely ignore this from a disk durability standpoint, although
it may of course be a nuisance that the disk doesn't power down when
shutting down OpenBSD (if that's indeed what happens, I'm not sure I fully
understood the description).
Also, "emergency retract" is a misnomer, the SMART attribute in quesetion
is actually called "Power-off Retract Count". Only Fujitsu (to my
knowledge) for some reason calles it Emergency Retract Cycle Count. In any
case it's a bullshit value to base any reliability predictions on, unless
maybe, MAYBE if it runs into the tens or hundreds of thousands.
Regards,
/Benny
On Sat, 3 Sep 2011, Marco Peereboom wrote:
Removing power from a running drive won't do anything to it. Just use
OpenBSD
and stop looking at worthless diagnostics tools.
On Sep 3, 2011, at 15:41, Steve <[email protected]> wrote:
Hi all,
I've got a strange situation with OpenBSD 4.9 on a new laptop, an Acer
Aspire 1430 with an Hitachi 500 GB SATA disk, model HTS545050B9A300. When
shutting down, OpenBSD does not spin down the disk, resulting in an
"emergency
unload" according to Smart terminology. Until I can resolve this
issue, I've
uninstalled OpenBSD from it, since smartctl reports in Slackware that
there
have been 17 "Power-off Retract" events so far, which could damage the
disk in
the long run. However I would really love to run OpenBSD on my laptop
for the
simple reason that I love it so much more than Linux.
Can anyone suggest what I could do to stop this from happening? I
found a
discussion on a FreeBSD mailing list identifying and trying to resolve
the
exact same thing through kernel recompilations:
http://freebsd.1045724.n5.nabble.com/Re-Spin-down-HDD-after-disk-sync-or-befo
re-power-off-td4043068.html
However, neither using FreeBSD nor patching the OpenBSD kernel would
be a
preferred choice for me. I'm sure there must be a simpler solution,
maybe a
sysctl setting I'm over-looking...? I've tried both IDE and AHCI modes
in the
BIOS with the same results.
Thanks,
Steve Schaller
