[CentOS] unable to read partition table in log

Mon May 18 21:49:55 UTC 2009
Robert Heller <heller at deepsoft.com>

At Mon, 18 May 2009 14:34:09 -0700 CentOS mailing list <centos at centos.org> wrote:

> 
> 
> 
> on 5-18-2009 1:04 PM P.A spake the following:
> > Hi recently I noticed in the messages log, the following error
> > 
> >  
> > 
> > May 18 15:59:52 mail kernel: sdb: assuming drive cache: write through
> > 
> > May 18 15:59:52 mail kernel: sdb : READ CAPACITY failed.
> > 
> > May 18 15:59:52 mail kernel: sdb : status=0, message=00, host=1, driver=00
> > 
> > May 18 15:59:52 mail kernel: sdb : sense not available.
> > 
> > May 18 15:59:52 mail kernel: sdb: assuming Write Enabled
> > 
> > May 18 15:59:52 mail kernel: sdb: assuming drive cache: write through
> > 
> > May 18 15:59:52 mail kernel:  sdb:<3>Buffer I/O error on device sdb,
> > logical block 0
> > 
> > May 18 15:59:52 mail kernel: Buffer I/O error on device sdb, logical block 0
> > 
> > May 18 15:59:52 mail last message repeated 5 times
> > 
> > May 18 15:59:52 mail kernel:  unable to read partition table
> > 
> >  
> > 
> > I’m not sure what sdb is since its not listed on my partition table
> > 
> >  
> > 
> > [root at mail srvadmin]# fdisk -l
> > 
> >  
> > 
> > Disk /dev/sda: 109.1 GB, 109196476416 bytes
> > 
> > 255 heads, 63 sectors/track, 13275 cylinders
> > 
> > Units = cylinders of 16065 * 512 = 8225280 bytes
> > 
> >  
> > 
> >    Device Boot      Start         End      Blocks   Id  System
> > 
> > /dev/sda1   *           1          13      104391   83  Linux
> > 
> > /dev/sda2              14       13275   106527015   8e  Linux LVM
> > 
> >  
> > 
> > [root at mail srvadmin]# df -h
> > 
> > Filesystem            Size  Used Avail Use% Mounted on
> > 
> > /dev/mapper/VolGroup00-LogVol00
> > 
> >                        99G   42G   52G  45% /
> > 
> > /dev/sda1              99M   44M   51M  47% /boot
> > 
> > none                  3.9G     0  3.9G   0% /dev/shm
> > 
> > [root at mail srvadmin]#
> > 
> >  
> > 
> > I looked at the hardware itself and all disk in this raid system are
> > fine, my question is, is this something I need to worry about and what
> > is causing this issue.
> > 
> > Although everything looking fine, my messages log is full of sdb complaints.
> > 
> 
> Does the system have memory card slots or a sd or cf reader? Some of those get
> detected as a scsi drive, but fail like this.

So do any removable SCSI or USB disk devices (Zip drives, Orb drives, etc.). 
Also any unformatted & unpartitioned USB mass storage devices will also
do this.  This could include USB thumb drives that have somehow lost
their file system and/or partition table.

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>                                                                                                                  

-- 
Robert Heller             -- 978-544-6933
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