Date: Thu, 23 Jul 2009 01:49:22 +0200 From: Arnaud Houdelette <tzim@tzim.net> To: Mark Stapper <stark@mapper.nl> Cc: stable@freebsd.org Subject: Re: ZFS RAIDZ and atacontrol spindown settings Message-ID: <4A67A582.8040702@tzim.net> In-Reply-To: <4A66B92C.8000800@mapper.nl> References: <4A643F5B.8080806@mapper.nl> <h421n2$1kt$1@ger.gmane.org> <4A656076.2060205@mapper.nl> <9bbcef730907210137udf7f90ax21aa530ab859f8a6@mail.gmail.com> <4A658205.5000709@mapper.nl> <4A65CE7F.8040906@tzim.net> <4A66B92C.8000800@mapper.nl>
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Mark Stapper wrote:
> Arnaud Houdelette wrote:
>
>> Mark Stapper a écrit :
>>
>>> Ivan Voras wrote:
>>>
>>>
>>>> 2009/7/21 Mark Stapper <stark@mapper.nl>:
>>>>
>>>>
>>>>> Ivan Voras wrote:
>>>>>
>>>>>
>>>>>> Mark Stapper wrote:
>>>>>>
>>>>>>
>>>>>>> Good day,
>>>>>>>
>>>>>>> I am the proud user of a FreeBSD 7.2 AMD64 system housing,
>>>>>>> amongst other
>>>>>>> things, a data server.
>>>>>>> My "server"(It's called "Yoshi") runs FreeBSD from a mirrored system
>>>>>>> disc, and has a zfs RAIDZ array with 4 discs for bulky data.
>>>>>>> As it is a home server, and I work during the day, these four
>>>>>>> discs were
>>>>>>> spinning happily all day long without much use for them doing so.
>>>>>>> To save the world(and money) I issued the command "atacontrol
>>>>>>> spindown
>>>>>>> 1800" for all the discs in my array spinning them down after thirty
>>>>>>> minutes of idle spinning.
>>>>>>> So far so good, me very happy! However, when I access the array
>>>>>>> after
>>>>>>> the discs have been spun down, it spins up the discs one after the
>>>>>>> other...
>>>>>>> Mind you one AFTER the other, taking 4*9 seconds to do a "ls"
>>>>>>> command on
>>>>>>> my music directory.
>>>>>>> Content as I am with the smooth down- and upspinning of the disks, I
>>>>>>> would like it better if the four discs would spin up simultaneously.
>>>>>>> Thus my question: "Is it possible to \"group\" discs to be spun up
>>>>>>> together, or to issue a custom command upon upspinning of a disc
>>>>>>> such as
>>>>>>> to spin up other disks?"
>>>>>>>
>>>>>>>
>>>>>> Good question but the answer is probably no - it really only depends
>>>>>> on how ZFS accesses the drives; if it accesses them in sequence, you
>>>>>> can't change it.
>>>>>>
>>>>>>
>>>>> I've been looking at writing a shell script which monitors
>>>>> /var/log/messages.
>>>>> something like:
>>>>>
>>>>> If last line in /var/log/messages is like "request while spun down.
>>>>> Starting."
>>>>> spinup disks
>>>>>
>>>>> couple of problems though, I should probably poll the kernel messages
>>>>> every second or so, but if I only check the last linee, I could
>>>>> miss the
>>>>> spinup message.
>>>>> I could count the number of lines in /var/log/messages and keep
>>>>> count of
>>>>> the number of lines i've seen. Problem with this approach is that it's
>>>>> not very efficient.
>>>>> So I was hoping there is a way to receive this kernel message
>>>>> directly.
>>>>> I am now thinking in the lines of a program which received a signal on
>>>>> new kernel messages available or something similar.
>>>>>
>>>>> Any thoughts?
>>>>>
>>>>>
>>>> You could do what "tail -f" does and simply hook a kqueue to get new
>>>> messages from the /var/log/messages file.
>>>>
>>>>
>>> I'll try that! thanks!
>>>
>>>
>>>
>> As I get quite the same issue with a 4 disk raidz pool, could you
>> please tell me the result of your tries ? which command do you use to
>> force the disks to spin up ?
>>
>> Thanks
>>
> I have been using a shell script containing:
> #!/bin.sh
> dd if=/dev/ad4 of=/dev/null count=1&
> dd if=/dev/ad6 of=/dev/null count=1&
> dd if=/dev/ad8 of=/dev/null count=1&
> dd if=/dev/ad10 of=/dev/null count=1&
>
Thanks.
FYI, I made the little script behind to speed up the spinup of the whole
pool, in case it be some use for anybody :
#!/bin/sh
wait-spinup() {
while true
do
read l
l=`echo $l | grep 'request while spun down'`
if [ -n "$l" -a "`date +%H%M%S`" != "$d" ]; then
d=`date +%H%M%S`
dd if=/dev/ad4 of=/dev/null count=1 2> /dev/null &
dd if=/dev/ad6 of=/dev/null count=1 2> /dev/null &
dd if=/dev/ad8 of=/dev/null count=1 2> /dev/null &
dd if=/dev/ad10 of=/dev/null count=1 2> /dev/null &
fi
done
}
tail -n 0 -F /var/log/messages | wait-spinup
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