Error attempting to read or write to /dev/st0: sense key Medium Error

[Herminio]

Dear all,

I am a newbie to linux servers and tape backups, and I have a problem performing a simple 'tar -cf' backup. 

The system in question:
Redhat 9.0 on a Dell PowerEdge 600SC with 
Adaptec AIC7XXX EISA/VLB/PCI SCSI HBA DRIVER, Rev 6.2.8

The tape drive is a DELL PowerVault 100T DDS4. It appears as 'Python 06408-XXX Rev: 9100' in /proc/scsi/scsi. It is the only SCSI device on a Adaptec 3960D Ultra160 SCSI adapter.

Using a brand new DDS-4 tape, I try the following:

[root at nccserver root]# tar cvf /dev/st0 data/ 
data/
... 
tar: /dev/st0: Wrote only 0 of 10240 bytes 
tar: Error is not recoverable: exiting now 

If I try reading the tape contents:

[root at nccserver root]# tar tvf /dev/st0 |more 
tar: /dev/st0: Cannot read: Input/output error 
tar: At beginning of tape, quitting now 
tar: Error is not recoverable: exiting now 

Some info about the tape drive and related hardware:

[root at nccserver root]# mt -f /dev/st0 status 
SCSI 2 tape drive: 
File number=0, block number=0, partition=0. 
Tape block size 512 bytes. Density code 0x26 <DDS-4 or QIC-4GB>. 
Soft error count since last status=0 
General status bits on (41010000): 
BOT ONLINE IM_REP_EN 

[root at nccserver root]# dmesg | grep st0 
Attached scsi tape st0 at scsi0, channel 0, id 6, lun 0 
st0: Block limits 1 - 16777215 bytes.
st0: Error with sense data: Info fld=0x3c, Current st09:00: sense key 
Medium Error
st0: Error with sense data: Info fld=0x0, Current st09:00: sense key 
Medium Error
st0: Error on write filemark.
st0: Error with sense data: Info fld=0x3c, Current st09:00: sense key 
Medium Error
st0: Error with sense data: Info fld=0x0, Current st09:00: sense key 
Medium Error
st0: Error on write filemark.

[root at nccserver root]# cat /proc/devices 
Character devices: 
1 mem 
2 pty 
3 ttyp 
4 ttyS 
5 cua 
7 vcs 
9 st 
10 misc
13 input 
29 fb 
36 netlink
109 lvm 
128 ptm
129 ptm
130 ptm
131 ptm
132 ptm
133 ptm
134 ptm
135 ptm 
136 pts
137 pts
138 pts
139 pts
140 pts
141 pts
142 pts
143 pts 
162 raw
180 usb
254 megadev 

Block devices: 
1 ramdisk 
2 fd 
7 loop
8 sd
9 md
11 sr
12 unnamed
14 unnamed
33 ide2
38 unnamed
39 unnamed
58 lvm
65 sd
66 sd

[root at nccserver root]# cat /proc/scsi/scsi 
Attached devices: 
Host: scsi0 Channel: 00 Id: 06 Lun: 00 
Vendor: ARCHIVE Model: Python 06408-XXX Rev: 9100 
Type: Sequential-Access ANSI SCSI revision: 03 
Host: scsi2 Channel: 00 Id: 00 Lun: 00 
Vendor: MegaRAID Model: LD0 RAID1 34678R Rev: 3.28 
Type: Direct-Access ANSI SCSI revision: 02
Host: scsi3 Channel: 00 Id: 00 Lun: 00 
Vendor: SAMSUNG Model: CDRW/DVD SM-348B Rev: T502 
Type: CD-ROM ANSI SCSI revision: 02

a pertion of  /var/log/messages:
Jan 13 11:06:30 nccmirror kernel: SCSI subsystem driver Revision: 1.00
Jan 13 11:06:30 nccmirror kernel: scsi0 : Adaptec AIC7XXX EISA/VLB/PCI SCSI HBA DRIVER, Rev 6.2.8
Jan 13 11:06:30 nccmirror kernel:         <Adaptec 3960D Ultra160 SCSI adapter>
Jan 13 11:06:30 nccmirror kernel:         aic7899: Ultra160 Wide Channel A, SCSI Id=7, 32/253 SCBs
Jan 13 11:06:30 nccmirror kernel:
Jan 13 11:06:30 nccmirror kernel: scsi1 : Adaptec AIC7XXX EISA/VLB/PCI SCSI HBA DRIVER, Rev 6.2.8
Jan 13 11:06:30 nccmirror kernel:         <Adaptec 3960D Ultra160 SCSI adapter>
Jan 13 11:06:30 nccmirror kernel:         aic7899: Ultra160 Wide Channel B, SCSI Id=7, 32/253 SCBs
Jan 13 11:06:30 nccmirror kernel:


I think the lines starting from dmesg, starting with

st0: Error with sense data: Info fld=0x??

Are providing information about the nature of the problem, but I don't know how to interpret them. Any help would be much appreciated.

Thanks.




Herminio Gonzalez
Clinical Trials and Services Unit
Oxford University
UK