Mailinglist Archive: opensuse (1606 mails)

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Re: [opensuse] Opensuse doesn't wait long enough for the disks to spin up before trrying to configure raid
  • From: Mike Myers <mikesm559@xxxxxxxxx>
  • Date: Sun, 31 Aug 2008 20:32:03 -0700 (PDT)
  • Message-id: <533072.3723.qm@xxxxxxxxxxxxxxxxxxxxxxxxxxx>
I agree with you that it doesn't seem to make sense to have the delay time
between spinup initiation and assembly stage to be fixed irrespective of disks.
Hopefully adjust the timeout will fix it, but something does seem wrong with
the way this is currently architected.

I am very sure there are no BIOS options to spin up the disks, either staggered
or all at once. I have an adaptec 1430SA, plus two SI3132 based serial ATA
controllers. The BIOS of all the cards has no such option, though the
motherboard ports I do believe obey the motherboard BIOS disk delay parameter.
And I know the Adaptec controller and the SI 3132 BIOS does not support port
multipliers - they only "see" the disk on port 0 of the PMP, not the other 4.
So since it only sees one disk, I do not believe that it is possible for it to
spin the other guys up.

The only code that understands PMP's are there is libata, so if staggered
spinup or group spinup (2 or 3 at a time) is to be implemented, it would have
to be done in the libata code. The only thing that happens now is spinup
during the hotplug sequence, and even thenj it's not explicitly sttable - I
couldn't do simultaneous spinup even if I wanted too. It would be good if the
software raid configuration that libata does would have these same capabilities
for controlling spinup and other items that hardware raid controllers do.
After all, software raid should be able to be much more flexible and
configurable than a hardware raid controller.

If I'm offtrack here, I'd love to be proven wrong, but I've built software raid
basd NAS's for 3 years now, and have always seen the process work as I've
described it.

thx
mike





----- Original Message ----
From: Brian K. White <brian@xxxxxxxxx>
To: opensuse@xxxxxxxxxxxx
Sent: Sunday, August 31, 2008 7:35:58 PM
Subject: Re: [opensuse] Opensuse doesn't wait long enough for the disks to spin
up before trrying to configure raid


----- Original Message -----
From: "Mike Myers" <mikesm559@xxxxxxxxx>
To: <opensuse@xxxxxxxxxxxx>
Sent: Saturday, August 30, 2008 3:31 PM
Subject: Re: [opensuse] Opensuse doesn't wait long enough for the disks to spin
up before trrying to configure raid


I don't think that's going to fix it. The way the libata
driver works is that it spins the disks up one at a time
(staggered spinup). Just powering the system on will not
cause the disks to spin up. After the start of the boot,
/ is mounted and the sata driver begins doing all of it's
work, finding the PMP's on the SATA ports, and then probing
each PMP, id'ing the disks and spinning them up, etc...
So this is all happening way after the boot is started.

Every piece of hardware I ever saw spun the disks up on it's own, and that
includes lots of scsi and sata and sas raid arrays, including the use of sata
port expanders/multiplexers. Usually the bios involved (maybe a raid card,
maybe a motherboard) offers an option to stagger the spinup, configureable
seconds between disks, or configurable seconds between sets of N(configurable)
disks at once, configurable seconds to wait in total, or all of the above.

Then libata will find every disk ready to go on the first try and that whole
sequence should shoot through fast and not screw up md mounting.

However I do think the way you are trying to fix it is the more correct fix.
The assmbly and mount stages should obviously block until the spinup stage is
done, and the spinup stage should obviously have a timeout per disk and no
fixed total timeout.

However-However... Even IF the raid card and mb offer no way to avoid starting
all disks at once, a box like that should probably have a dual or triple
redundant, hot-swap power supply anyways. (you bought 18 hot swap disks but
only a plain jane single not-hot-swap ps?) It might be too much for one power
supply to spin up all at once, but as long as you have both plugged in and both
work, then no problem. You're only vulnerable when one ps dies until you get
it's replacement in. And since they're hot swap, you can have the spare sitting
there on hand already and pop it in immediately.

--
Brian K. White brian@xxxxxxxxx http://www.myspace.com/KEYofR
+++++[>+++[>+++++>+++++++<<-]<-]>>+.>.+++++.+++++++.-.[>+<---]>++.
filePro BBx Linux SCO FreeBSD #callahans Satriani Filk!

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