Example: Mount External USB Storage under OpenBSD
Intro
A friend had an extra My Book and sold it to me cheap. A 320GB external USB drive, and I hadn't put a USB device near the OpenBSD server before. It took a little poking and since I didn't see a straightforward list on a quick google search, wrote my steps down for next time.
Steps
Find the scsi id of the usb device, it may be that the first plugged in is always sd0, but to be sure use dmesg. Then, to find which partition is setup how (which fstype) use disklabel disk. That should provide all the info needed to plug into mount -t fstype disk dir. If that reminder doesn't work, continue on for examples below.
Find scsi special
My Western Digital My Book shows up as sd0, it is evident in syslog messages and dmesg:
lmno$ tail /var/log/messages
Jan 24 21:33:50 lmno /bsd: umass0: using SCSI over Bulk-Only
Jan 24 21:33:50 lmno /bsd: scsibus1 at umass0: 2 targets
Jan 24 21:33:50 lmno /bsd: sd0 at scsibus1 targ 1 lun 0: SCSI4 0/direct fixed
Jan 24 21:33:50 lmno /bsd: sd0: 305245MB, 305245 cyl, 64 head, 32 sec, 512 bytes/sec, 625142448 sec total
Jan 24 21:33:50 lmno /bsd: uhidev0 at uhub3 port 6 configuration 1 interface 1
Jan 24 21:33:50 lmno /bsd:
Jan 24 21:33:50 lmno /bsd: uhidev0: Western Digital My Book, rev 2.00/10.16, addr 2, iclass 3/0
Jan 24 21:33:50 lmno /bsd: uhid0 at uhidev0: input=1, output=2, feature=0
Jan 24 21:58:14 lmno /bsd: udf_mount: enforcing read-only mode
Jan 24 22:00:01 lmno syslogd: restart
lmno$ dmesg
...
umass0 at uhub3 port 6 configuration 1 interface 0
umass0: Western Digital My Book, rev 2.00/10.16, addr 2
umass0: using SCSI over Bulk-Only
scsibus1 at umass0: 2 targets
sd0 at scsibus1 targ 1 lun 0: SCSI4 0/direct fixed
sd0: 305245MB, 305245 cyl, 64 head, 32 sec, 512 bytes/sec, 625142448 sec total
uhidev0 at uhub3 port 6 configuration 1 interface 1
uhidev0: Western Digital My Book, rev 2.00/10.16, addr 2, iclass 3/0
...
Verify fstype
Verify the filesystem in use is msdos under openbsd, using partition i:
lmno$ sudo disklabel sd0
Password:
disklabel: warning, DOS partition table with no valid OpenBSD partition
# /dev/rsd0c:
type: SCSI
disk: SCSI disk
label: My Book
flags:
bytes/sector: 512
sectors/track: 32
tracks/cylinder: 64
sectors/cylinder: 2048
cylinders: 305245
total sectors: 625142448
rpm: 3600
interleave: 1
trackskew: 0
cylinderskew: 0
headswitch: 0 # microseconds
track-to-track seek: 0 # microseconds
drivedata: 0
16 partitions:
# size offset fstype [fsize bsize cpg]
c: 625142448 0 unused 0 0 # Cyl 0 -305245*
i: 625137282 63 MSDOS # Cyl 0*-305242*
Mount the drive
Create a destination node and mount the device on it
lmno$ sudo mkdir -p /mnt/mybook/
lmno$ sudo mount_msdos /dev/sd0i /mnt/mybook/
lmno$ df -h /mnt/mybook
Filesystem Size Used Avail Capacity Mounted on
/dev/sd0i 298G 83.3G 215G 28% /mnt/mybook
Unmount Drive
Rather than force things to umount when done with /mnt/mybook for awhile, I had to check into why it wouldn't umount and it turned out I had restarted mysql while pwd was on the mouned drive.
lmno$ sudo umount /mnt/mybook/
Password:
umount: /mnt/mybook: Device busy
lmno$ fstat | grep mnt
root sh 26544 wd /mnt/mybook 371098 ?rwSr-S--T r 255593762450
lmno$ ps auwx | grep 26544
root 26544 0.0 0.0 548 4 p0 I 1:42AM 0:00.02 /bin/sh /usr/local/bin/mysqld_safe
lmno$ sudo kill_mysqld
STOPPING server from pid file /var/mysql/lmno.pid
090125 12:41:32 mysqld ended
lmno$ sudo umount /mnt/mybook/
lmno$ sudo start_mysqld
Starting mysqld daemon with databases from /var/mysql
.ln: /var/run/mysql/mysql.sock: File exists
done