I have no experience with the DELL SAS controller, but usually the
advantage of using a simple controller (instead of a RAID card) is that
you can use full SMART directly.
$ sudo smartctl -a /dev/sda
=== START OF INFORMATION SECTION ===
Device Model: INTEL SSDSA2BW300G3H
Serial Number: PEPR2381003E300EGN
Personally, I make sure that I know which serial number drive is in
which bay, so I can easily tell which drive I'm talking about.
So you can use SMART both to notice (pre)failing disks -and- to
physically identify them.
The same smartctl command also returns the health status like so:
233 Media_Wearout_Indicator 0x0032 099 099 000 Old_age Always
- 0
This specific SSD has 99% media lifetime left, so it's in the green. But
it will continue to gradually degrade, and at some time It'll hit a
percentage where I like to replace it. To keep an eye on the speed of
decay, I'm graphing those SMART values in Cacti. That way I can somewhat
predict how long a disk will last, especially SSD's which die very
gradually.
Erik.
On 12-11-14 14:43, JF Le Fillâtre wrote:
>
> Hi,
>
> May or may not work depending on your JBOD and the way it's identified
> and set up by the LSI card and the kernel:
>
> cat /sys/block/sdX/../../../../sas_device/end_device-*/bay_identifier
>
> The weird path and the wildcards are due to the way the sysfs is set up.
>
> That works with a Dell R520, 6GB HBA SAS cards and Dell MD1200s, running
> CentOS release 6.5.
>
> Note that you can make your life easier by writing an udev script that
> will create a symlink with a sane identifier for each of your external
> disks. If you match along the lines of
>
> KERNEL=="sd*[a-z]", KERNELS=="end_device-*:*:*"
>
> then you'll just have to cat "/sys/class/sas_device/${1}/bay_identifier"
> in a script (with $1 being the $id of udev after that match, so the
> string "end_device-X:Y:Z") to obtain the bay ID.
>
> Thanks,
> JF
>
>
>
> On 12/11/14 14:05, SCHAER Frederic wrote:
>> Hi,
>>
>>
>>
>> I’m used to RAID software giving me the failing disks slots, and most
>> often blinking the disks on the disk bays.
>>
>> I recently installed a DELL “6GB HBA SAS” JBOD card, said to be an LSI
>> 2008 one, and I now have to identify 3 pre-failed disks (so says
>> S.M.A.R.T) .
>>
>>
>>
>> Since this is an LSI, I thought I’d use MegaCli to identify the disks
>> slot, but MegaCli does not see the HBA card.
>>
>> Then I found the LSI “sas2ircu” utility, but again, this one fails at
>> giving me the disk slots (it finds the disks, serials and others, but
>> slot is always 0)
>>
>> Because of this, I’m going to head over to the disk bay and unplug the
>> disk which I think corresponds to the alphabetical order in linux, and
>> see if it’s the correct one…. But even if this is correct this time, it
>> might not be next time.
>>
>>
>>
>> But this makes me wonder : how do you guys, Ceph users, manage your
>> disks if you really have JBOD servers ?
>>
>> I can’t imagine having to guess slots that each time, and I can’t
>> imagine neither creating serial number stickers for every single disk I
>> could have to manage …
>>
>> Is there any specific advice reguarding JBOD cards people should (not)
>> use in their systems ?
>>
>> Any magical way to “blink” a drive in linux ?
>>
>>
>>
>> Thanks && regards
>>
>>
>>
>> _______________________________________________
>> ceph-users mailing list
>> ceph-users@lists.ceph.com
>> http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
>>
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>
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