3ware and scsi ids

3ware and scsi ids

[Deas, Jim]

I am currently using 3wares products to create 2T raids.
To increase performance on my NAS type boxes I am
using software raids.
 My problem relates to a falure of a IDE drive.
Once a drive fails the next boot of the machine remaps all scsi ids.
so /dev/sda-adi becomes /dev/sda-sdh.
In short, if /dev/sdb dies, all raids become bad as all scsi ids
shift down making my raidtab file now point at the wrong drives.
(I assume this will also be a possible problem when I use
my USB dongle to update software.)

 Is there a way to hard assign logical /dev/sd(x) in the driver
so they will always map the same ide port on the 3ware controllers?
3ware is no help on this. They say it is the bios/system and they
have no control over this.

Thanks
J. Deas

Re: 3ware and scsi ids

[Alan Cox]

On Maw, 2003-06-03 at 19:05, Deas, Jim wrote:
> In short, if /dev/sdb dies, all raids become bad as all scsi ids
> shift down making my raidtab file now point at the wrong drives.
> (I assume this will also be a possible problem when I use
> my USB dongle to update software.)

Yes that sometimes comes up, along with a wonderful variant where 
USB cameras beat the PCI sound card to being first sound device
> 
>  Is there a way to hard assign logical /dev/sd(x) in the driver
> so they will always map the same ide port on the 3ware controllers?
> 3ware is no help on this. They say it is the bios/system and they
> have no control over this.

Correct.

The vendor Linux systems mostly support mount by label so you can
avoid using anything but the file system label to find a disk if
something vanishes.

So you'll see lines like this in /etc/fstab

LABEL=/boot             /boot                   ext3    defaults       1
2

Re: 3ware and scsi ids

[Friedrich Lobenstock]

Deas, Jim wrote:
> I am currently using 3wares products to create 2T raids.
> To increase performance on my NAS type boxes I am
> using software raids.
>  My problem relates to a falure of a IDE drive.
> Once a drive fails the next boot of the machine remaps all scsi ids.
> so /dev/sda-adi becomes /dev/sda-sdh.
> In short, if /dev/sdb dies, all raids become bad as all scsi ids
> shift down making my raidtab file now point at the wrong drives.
> (I assume this will also be a possible problem when I use
> my USB dongle to update software.)
> 
>  Is there a way to hard assign logical /dev/sd(x) in the driver
> so they will always map the same ide port on the 3ware controllers?
> 3ware is no help on this. They say it is the bios/system and they
> have no control over this.

You'd better use mdadm instead of the raidtools.

The config file for mdadm looks like this:
# cat /etc/mdadm.conf
DEVICE /dev/hd* /dev/sd*
ARRAY /dev/md0 level=raid1 num-devices=2 UUID=52094036:b2e9cf8b:4267c923:750757da

So you do not have to worry about which drive gets assigned which
scsi id.

A
    /sbin/mdadm --assemble --scan
will do the trick.

Get it at http://www.cse.unsw.edu.au/~neilb/source/mdadm/

-- 
MfG / Regards
Friedrich Lobenstock
____________________________________________________________________
Friedrich Lobenstock                       Linux Services Lobenstock
URL: http://www.lsl.at/                         Email: fl@fl.priv.at
____________________________________________________________________

RE: 3ware and scsi ids

[Deas, Jim]

I have never seen labels in the raidtab.
fstab yes. raidtab no. Is it possible?
Is this a better solution than LVM?
LVM seem to insert yet another layer.
I would like to avoid that if possible.

JD


-----Original Message-----
From: Alan Cox [mailto:alan@lxorguk.ukuu.org.uk]
Sent: Tuesday, June 03, 2003 12:58 PM
To: Deas, Jim
Cc: linux-scsi@vger.kernel.org
Subject: Re: 3ware and scsi ids


On Maw, 2003-06-03 at 19:05, Deas, Jim wrote:
> In short, if /dev/sdb dies, all raids become bad as all scsi ids
> shift down making my raidtab file now point at the wrong drives.
> (I assume this will also be a possible problem when I use
> my USB dongle to update software.)

Yes that sometimes comes up, along with a wonderful variant where 
USB cameras beat the PCI sound card to being first sound device
> 
>  Is there a way to hard assign logical /dev/sd(x) in the driver
> so they will always map the same ide port on the 3ware controllers?
> 3ware is no help on this. They say it is the bios/system and they
> have no control over this.

Correct.

The vendor Linux systems mostly support mount by label so you can
avoid using anything but the file system label to find a disk if
something vanishes.

So you'll see lines like this in /etc/fstab

LABEL=/boot             /boot                   ext3    defaults       1
2

RE: 3ware and scsi ids

[Alan Cox]

On Maw, 2003-06-03 at 23:16, Deas, Jim wrote:
> I have never seen labels in the raidtab.
> fstab yes. raidtab no. Is it possible?
> Is this a better solution than LVM?
> LVM seem to insert yet another layer.
> I would like to avoid that if possible.

Ah sorry I misunderstood your original message slightly.

raidtab doesn't have any labels. This might be useful
however. The Dell guys wrote a tool that generates consistant
naming using device serial info

	http://www.lerhaupt.com/devlabel/

RE: 3ware and scsi ids

[Deas, Jim]

Have you tried this on the 3ware product? They do not
return scsi data as a normal drive would. As far as I
can tell, without making a 3ware specific system call
you can not get a unique serial number from the drives.

Regards,
J. Deas


-----Original Message-----
From: Friedrich Lobenstock [mailto:fl@fl.priv.at]
Sent: Friday, June 06, 2003 4:51 PM
To: Linux RAID Mailing Liste
Cc: linux-scsi@vger.kernel.org
Subject: Re: 3ware and scsi ids


Deas, Jim wrote:
> I am currently using 3wares products to create 2T raids.
> To increase performance on my NAS type boxes I am
> using software raids.
>  My problem relates to a falure of a IDE drive.
> Once a drive fails the next boot of the machine remaps all scsi ids.
> so /dev/sda-adi becomes /dev/sda-sdh.
> In short, if /dev/sdb dies, all raids become bad as all scsi ids
> shift down making my raidtab file now point at the wrong drives.
> (I assume this will also be a possible problem when I use
> my USB dongle to update software.)
> 
>  Is there a way to hard assign logical /dev/sd(x) in the driver
> so they will always map the same ide port on the 3ware controllers?
> 3ware is no help on this. They say it is the bios/system and they
> have no control over this.

You'd better use mdadm instead of the raidtools.

The config file for mdadm looks like this:
# cat /etc/mdadm.conf
DEVICE /dev/hd* /dev/sd*
ARRAY /dev/md0 level=raid1 num-devices=2 UUID=52094036:b2e9cf8b:4267c923:750757da

So you do not have to worry about which drive gets assigned which
scsi id.

A
    /sbin/mdadm --assemble --scan
will do the trick.

Get it at http://www.cse.unsw.edu.au/~neilb/source/mdadm/

-- 
MfG / Regards
Friedrich Lobenstock
____________________________________________________________________
Friedrich Lobenstock                       Linux Services Lobenstock
URL: http://www.lsl.at/                         Email: fl@fl.priv.at
____________________________________________________________________


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Re: 3ware and scsi ids

[Paul Clements]

"Deas, Jim" wrote:
> 
> Have you tried this on the 3ware product? They do not
> return scsi data as a normal drive would. As far as I
> can tell, without making a 3ware specific system call
> you can not get a unique serial number from the drives.

The UUID referenced below is gotten from the md device superblock (data
written to the end of the disk) so there shouldn't be any issues with
devices that do not return a valid SCSI serial number or device ID.

--
Paul 


 
> -----Original Message-----
> From: Friedrich Lobenstock [mailto:fl@fl.priv.at]
> Sent: Friday, June 06, 2003 4:51 PM
> To: Linux RAID Mailing Liste
> Cc: linux-scsi@vger.kernel.org
> Subject: Re: 3ware and scsi ids
> 
> Deas, Jim wrote:
> > I am currently using 3wares products to create 2T raids.
> > To increase performance on my NAS type boxes I am
> > using software raids.
> >  My problem relates to a falure of a IDE drive.
> > Once a drive fails the next boot of the machine remaps all scsi ids.
> > so /dev/sda-adi becomes /dev/sda-sdh.
> > In short, if /dev/sdb dies, all raids become bad as all scsi ids
> > shift down making my raidtab file now point at the wrong drives.
> > (I assume this will also be a possible problem when I use
> > my USB dongle to update software.)
> >
> >  Is there a way to hard assign logical /dev/sd(x) in the driver
> > so they will always map the same ide port on the 3ware controllers?
> > 3ware is no help on this. They say it is the bios/system and they
> > have no control over this.
> 
> You'd better use mdadm instead of the raidtools.
> 
> The config file for mdadm looks like this:
> # cat /etc/mdadm.conf
> DEVICE /dev/hd* /dev/sd*
> ARRAY /dev/md0 level=raid1 num-devices=2 UUID=52094036:b2e9cf8b:4267c923:750757da
> 
> So you do not have to worry about which drive gets assigned which
> scsi id.
> 
> A
>     /sbin/mdadm --assemble --scan
> will do the trick.
> 
> Get it at http://www.cse.unsw.edu.au/~neilb/source/mdadm/
> 
> --
> MfG / Regards
> Friedrich Lobenstock
> ____________________________________________________________________
> Friedrich Lobenstock                       Linux Services Lobenstock
> URL: http://www.lsl.at/                         Email: fl@fl.priv.at
> ____________________________________________________________________
> 
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