How can I tell what drive is sdb?

How can I tell what drive is sdb?

[Rick Bragg]

Hi,

I have a system with raid10 running Ubuntu 8.10.  It uses a
"promise"card

# lsusb
..
01:02.0 Mass storage controller: Promise Technology, Inc. PDC40718 (SATA
300 TX4) (rev 02)
..

I have 4 identical disks on it and they show up as /dev/sda, b, c, and
d.

However, sdb needs to be replaced.  How can I tell which drive is sdb?
Is there a way to identify what drive is what?

Thanks
Rick

Re: How can I tell what drive is sdb?

[Matt Garman]

On Wed, Jan 27, 2010 at 8:03 AM, Rick Bragg <lists@gmnet.net> wrote:
> I have 4 identical disks on it and they show up as /dev/sda, b, c, and
> d.
>
> However, sdb needs to be replaced.  How can I tell which drive is sdb?
> Is there a way to identify what drive is what?

Sometimes you can infer from dmesg.  E.g., type "dmesg | less" then
scroll until you see where sdb is initialized; it might show the model
and serial number of the drive.

Another approach is to use smartctl, i.e.: "sudo smartctl -a
/dev/sdb".  This will definitely show you the model and serial number.
 You can also use hdparm for the same effect: "sudo hdparm -I
/dev/sdb".

I'm sure there's more ways, but those are the first that come to mind.

-Matt
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Re: How can I tell what drive is sdb?

[Jan Ceuleers]

Matt Garman wrote:
>> Is there a way to identify what drive is what?
> 
> Sometimes you can infer from dmesg.  E.g., type "dmesg | less" then
> scroll until you see where sdb is initialized; it might show the model
> and serial number of the drive.
> 
> Another approach is to use smartctl, i.e.: "sudo smartctl -a
> /dev/sdb".  This will definitely show you the model and serial number.
>  You can also use hdparm for the same effect: "sudo hdparm -I
> /dev/sdb".
> 
> I'm sure there's more ways, but those are the first that come to mind.

I'm guessing that the OP is looking for ways to identify disks without disassembling them all.

In the networking world, you can ask the system to tell you which network interface is which, by blinking the network LEDs (using ethtool -p). Is there something similar for disks?

Re: How can I tell what drive is sdb?

[Steven Haigh]

On 28/01/2010, at 1:18 AM, Jan Ceuleers wrote:

> Matt Garman wrote:
>>> Is there a way to identify what drive is what?
>> 
>> Sometimes you can infer from dmesg.  E.g., type "dmesg | less" then
>> scroll until you see where sdb is initialized; it might show the model
>> and serial number of the drive.
>> 
>> Another approach is to use smartctl, i.e.: "sudo smartctl -a
>> /dev/sdb".  This will definitely show you the model and serial number.
>> You can also use hdparm for the same effect: "sudo hdparm -I
>> /dev/sdb".
>> 
>> I'm sure there's more ways, but those are the first that come to mind.
> 
> I'm guessing that the OP is looking for ways to identify disks without disassembling them all.
> 
> In the networking world, you can ask the system to tell you which network interface is which, by blinking the network LEDs (using ethtool -p). Is there something similar for disks?

I used a similar method. I have a SATA enclosure that takes 3 x 5.25" bays and gives me 4 x hot swap SATA bays.

As each bay has a power and an activity LED I can do something simple like:
			dd if=/dev/sdb of=/dev/null

The bay that has sdb will have a constantly on activity light.

If you don't have enclosures, then this becomes somewhat difficult.

--
Steven Haigh

Email: netwiz@crc.id.au
Web: http://www.crc.id.au
Phone: (03) 9001 6090 - 0412 935 897
Fax: (03) 8338 0299

Re: How can I tell what drive is sdb?

[Matt Garman]

On Wed, Jan 27, 2010 at 8:21 AM, Steven Haigh <netwiz@crc.id.au> wrote:
>
> On 28/01/2010, at 1:18 AM, Jan Ceuleers wrote:
>
>> Matt Garman wrote:
>>>> Is there a way to identify what drive is what?
>>>
>>> Sometimes you can infer from dmesg.  E.g., type "dmesg | less" then
>>> scroll until you see where sdb is initialized; it might show the model
>>> and serial number of the drive.
>>>
>>> Another approach is to use smartctl, i.e.: "sudo smartctl -a
>>> /dev/sdb".  This will definitely show you the model and serial number.
>>> You can also use hdparm for the same effect: "sudo hdparm -I
>>> /dev/sdb".
>>>
>>> I'm sure there's more ways, but those are the first that come to mind.
>>
>> I'm guessing that the OP is looking for ways to identify disks without disassembling them all.
>>
>> In the networking world, you can ask the system to tell you which network interface is which, by blinking the network LEDs (using ethtool -p). Is there something similar for disks?
>
> I used a similar method. I have a SATA enclosure that takes 3 x 5.25" bays and gives me 4 x hot swap SATA bays.
>
> As each bay has a power and an activity LED I can do something simple like:
>                        dd if=/dev/sdb of=/dev/null
>
> The bay that has sdb will have a constantly on activity light.
>
> If you don't have enclosures, then this becomes somewhat difficult.

Depending on how the drives are mounted and their proximity to one
another, in the absence of LEDs, you might be able to listen to and/or
feel the drives will running dd, and possibly determine which is
which.

Another tedious approach: use smartctl or hdparm as suggested above to
get an initial mapping of /dev/sdX to serial number.  Then, disconnect
the SATA cable of all but one drive, and reboot.  Now look at what
/dev/sda's serial number is, and compare that to the initial mapping.
Eventually /dev/sda will correspond to /dev/sdb when all drives are
connected.

If the controller supports hotswap, you could do something similar
without so many reboots.

This scheme makes the assumption that it's easier to pull SATA cables
than just look at the drive's serial numbers.
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Re: How can I tell what drive is sdb?

[Goswin von Brederlow]

Matt Garman <matthew.garman@gmail.com> writes:

> On Wed, Jan 27, 2010 at 8:21 AM, Steven Haigh <netwiz@crc.id.au> wrote:
>>
>> On 28/01/2010, at 1:18 AM, Jan Ceuleers wrote:
>>
>>> Matt Garman wrote:
>>>>> Is there a way to identify what drive is what?
>>>>
>>>> Sometimes you can infer from dmesg.  E.g., type "dmesg | less" then
>>>> scroll until you see where sdb is initialized; it might show the model
>>>> and serial number of the drive.
>>>>
>>>> Another approach is to use smartctl, i.e.: "sudo smartctl -a
>>>> /dev/sdb".  This will definitely show you the model and serial number.
>>>> You can also use hdparm for the same effect: "sudo hdparm -I
>>>> /dev/sdb".
>>>>
>>>> I'm sure there's more ways, but those are the first that come to mind.
>>>
>>> I'm guessing that the OP is looking for ways to identify disks without disassembling them all.
>>>
>>> In the networking world, you can ask the system to tell you which network interface is which, by blinking the network LEDs (using ethtool -p). Is there something similar for disks?
>>
>> I used a similar method. I have a SATA enclosure that takes 3 x 5.25" bays and gives me 4 x hot swap SATA bays.
>>
>> As each bay has a power and an activity LED I can do something simple like:
>>                        dd if=/dev/sdb of=/dev/null
>>
>> The bay that has sdb will have a constantly on activity light.
>>
>> If you don't have enclosures, then this becomes somewhat difficult.
>
> Depending on how the drives are mounted and their proximity to one
> another, in the absence of LEDs, you might be able to listen to and/or
> feel the drives will running dd, and possibly determine which is
> which.

Shut down the raid arry (or just don't access it), set the spin down
time to 10s with hdparm and run dd if=/dev/sdb of=/dev/null. All but sdb
should spin down and then you should be able to hear/feel the activity.

Some drives also have a small led onboard which you see if you run the
system opened.

MfG
        Goswin

PS: If you have to take the system offline and disassemble the drives to
find the right one then write down the serial number for each drive and
stick is some place visible when reassembled. If you lack space a color
coded dot or a number combined with a lookup table for color/numer ->
serial is also helpfull.

MfG
        Goswin
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Re: How can I tell what drive is sdb?

[Nagilum]

----- Message from matthew.garman@gmail.com ---------
     Date: Wed, 27 Jan 2010 08:29:50 -0600
     From: Matt Garman <matthew.garman@gmail.com>
  Subject: Re: How can I tell what drive is sdb?
       To: Steven Haigh <netwiz@crc.id.au>
       Cc: linux-raid@vger.kernel.org


> On Wed, Jan 27, 2010 at 8:21 AM, Steven Haigh <netwiz@crc.id.au> wrote:
>>
>> On 28/01/2010, at 1:18 AM, Jan Ceuleers wrote:
>>
>>> Matt Garman wrote:
>>>>> Is there a way to identify what drive is what?
>>>>
> Another tedious approach: use smartctl or hdparm as suggested above to
> get an initial mapping of /dev/sdX to serial number.  Then, disconnect
> the SATA cable of all but one drive, and reboot.  Now look at what
> /dev/sda's serial number is, and compare that to the initial mapping.
> Eventually /dev/sda will correspond to /dev/sdb when all drives are
> connected.
>
> If the controller supports hotswap, you could do something similar
> without so many reboots.
>
> This scheme makes the assumption that it's easier to pull SATA cables
> than just look at the drive's serial numbers.

blkid could also be used to identify the drives.
It should work with all types of drives SCSI/SATA/PATA/USB/...


----- End message from matthew.garman@gmail.com -----



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Re: How can I tell what drive is sdb?

[Kristleifur Daðason]

On Wed, Jan 27, 2010 at 2:03 PM, Rick Bragg <lists@gmnet.net> wrote:
> Hi,
>
> I have a system with raid10 running Ubuntu 8.10.  It uses a
> "promise"card
>
> # lsusb
> ..
> 01:02.0 Mass storage controller: Promise Technology, Inc. PDC40718 (SATA
> 300 TX4) (rev 02)
> ..
>
> I have 4 identical disks on it and they show up as /dev/sda, b, c, and
> d.
>
> However, sdb needs to be replaced.  How can I tell which drive is sdb?
> Is there a way to identify what drive is what?
>
> Thanks
> Rick
>

I think you can use the wonderful 'lshw' utility for this. It tells
you what serial numbers the disks have, and then you can look at the
labels on the drives to see which one has what serial number.

If this doesn't work out, you can PROBABLY stop the array and PROBABLY
hotswap the disks in and out, running 'watch -n0 -d "dmesg | tail"' to
see what the kernel says. It will tell you what drive you have just
unplugged. But if you do this - BE CAREFUL - and I can't vouch that
this is OK as I've never done this. I'm only guessing at theory.

Good luck!

-- Kristleifur
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Re: How can I tell what drive is sdb?

[Zdenek Kaspar]

Dne 27.1.2010 15:03, Rick Bragg napsal(a):
> Hi,
> 
> I have a system with raid10 running Ubuntu 8.10.  It uses a
> "promise"card
> 
> # lsusb
> ..
> 01:02.0 Mass storage controller: Promise Technology, Inc. PDC40718 (SATA
> 300 TX4) (rev 02)
> ..
> 
> I have 4 identical disks on it and they show up as /dev/sda, b, c, and
> d.
> 
> However, sdb needs to be replaced.  How can I tell which drive is sdb?
> Is there a way to identify what drive is what?
> 
> Thanks
> Rick

Hi

Check serial number of drive via hdparm -I /dev/sdb or looks into
/dev/disk/by-id. Write carefully serial number and shutdown & replace
correct drive :)

HTH, Z.

Re: How can I tell what drive is sdb?

[Jon Hardcastle]

--- On Wed, 27/1/10, Rick Bragg <lists@gmnet.net> wrote:

> From: Rick Bragg <lists@gmnet.net>
> Subject: How can I tell what drive is sdb?
> To: linux-raid@vger.kernel.org
> Date: Wednesday, 27 January, 2010, 14:03
> Hi,
> 
> I have a system with raid10 running Ubuntu 8.10.  It
> uses a
> "promise"card
> 
> # lsusb
> ..
> 01:02.0 Mass storage controller: Promise Technology, Inc.
> PDC40718 (SATA
> 300 TX4) (rev 02)
> ..
> 
> I have 4 identical disks on it and they show up as
> /dev/sda, b, c, and
> d.
> 
> However, sdb needs to be replaced.  How can I tell
> which drive is sdb?
> Is there a way to identify what drive is what?
> 
> Thanks
> Rick
> 

I had this problem, and and as it is a mare removing the drives to identify what one is what.. When i needed to reorganise my physical drive order i took the liberty of writing on the sides/back of each drive a short incrementing ID that tallys to a spreadsheet of serial numbers that i gleaned from smartctl.


      
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