Handeling removable disks under ESATA: Difference between revisions

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==to mount a disk==
These are (terse) write-ups of how to mount/unmount, as well a format disks, on the gs and dgs machines using the ESATA interface (works for usb as well).


==to unmount the disk again==
==To mount a Disk==


==to format a disk==
power disk up and type 'dmesg' to see what device name the computer chose. You should see something like this at the bottom of the list:
(NOTE: it may take a little while before the disk is recognized!!)


==setting up sudo==
.
.
.
[1624926.943952] usb 2-1: Product: STORE N GO
[1624926.943954] usb 2-1: Manufacturer: Verbatim
[1624926.943956] usb 2-1: SerialNumber: 07A3130929761542
[1624926.944802] scsi22 : usb-storage 2-1:1.0
[1624927.978847] scsi 22:0:0:0: Direct-Access    Verbatim STORE N GO      5.00 PQ: 0 ANSI: 0 CCS
[1624927.983253] sd 22:0:0:0: Attached scsi generic sg8 type 0
[1624928.496834] sd 22:0:0:0: [sdd] 7827456 512-byte logical blocks: (4.00 GB/3.73 GiB)
[1624928.498952] sd 22:0:0:0: [sdd] Write Protect is off
[1624928.498955] sd 22:0:0:0: [sdd] Mode Sense: 03 41 00 00
[1624928.501080] sd 22:0:0:0: [sdd] No Caching mode page present
[1624928.501084] sd 22:0:0:0: [sdd] Assuming drive cache: write through
[1624928.508574] sd 22:0:0:0: [sdd] No Caching mode page present
[1624928.508577] sd 22:0:0:0: [sdd] Assuming drive cache: write through
[1624928.530109]  sdd: sdd1
[1624928.535695] sd 22:0:0:0: [sdd] No Caching mode page present
[1624928.535698] sd 22:0:0:0: [sdd] Assuming drive cache: write through
[1624928.535701] sd 22:0:0:0: [sdd] Attached SCSI removable disk
[1624928.869338] SELinux: initialized (dev sdd1, type vfat), uses genfs_contexts
[1625347.268862] SELinux: initialized (dev sdd1, type vfat), uses genfs_contexts
 
or use
 
  lsblk
 
to see what disks are there. Not all systems have this handy utility.
 
then do
 
  sudo e2label /dev/sdd1
 
to see if the disk has an identifying label (see how to give a partition an identifying  label below); which you can then use as
 
  mkdir ~/esata/`sudo e2label /dev/sdd1`
  sudo /bin/mount /dev/sdd1 ~/esata/`sudo e2label /dev/sdd1`
  lsblk
  df | grep `sudo e2label /dev/sdd1`
 
 
==To Unmount the Disk Again==
 
  sync;sync;sync
  sudo /bin/umount /dev/sdd1
 
If you cannot unmount the disk, make sure you (or someone else) have not cd'ed to the disk in some window somewhere. Sometimes 'lsof | grep cwd' is useful in order to reveal who is cd'ed to the disk
 
 
==Trouble Unmounting a USB Disk==
 
Sometimes a user has cd'ed to a USB disk in some window (shell)
and then if someone else tries
to unmount the disk they will get a message like this:
 
  umount: /media/120514a: umount failed: Operation not permitted
 
The solution is to find the offending process and kill it ''cold''.
If the disk is labeled '120514a', then the steps are:
 
  lsof | grep 120514a
 
you might see something like this
 
  bash      8367      dgs  cwd      DIR      8,49    20480  61341743 /media/120514a/user/cs
 
you can now kill this offending process as
 
  kill -9 8367
 
and then you can do
 
  umount /media/120514a
 
==To Format a Disk==
 
WARNING: do not format the wrong disk, our you could get into big trouble!! If you are uncertain about how to format a disk, it is best to ask for help.
 
follow the procedure under 'to mount a disk:' to find the device name. Here we will assume '/dev/sdd'
 
partition the disk using fdisk:
 
  sudo /sbin/fdisk /dev/sdd
 
typically, for a new disk, you would simply say:
  p
  n
  p
  1
  hit return for default
  hit return for default
  w
 
this will create the partition '/dev/sdd1' which we will now impose a linux EXT4 file system on as
sudo /sbin/mkfs.ext4 -m 0 /dev/sdd1
 
to be able to write to the 5% of the disk that is normally reserved for root. For a data disk this is OK, but for a system disk it is a bad idea.
 
On some machines this takes a long time (e.g., scientific linux) , on others it is very fast (e.g., fedora 15)
 
It is a good idea to give the disk a UNIQUE label that makes sense to you, maybe just the date and a serial character:
 
  sudo /sbin/e2label /dev/sdd1  20120611a
 
With this label, if this disk is mounted automatically as a usb disk, it will then come up as /media/20120611a
 
You can now mount the disk using the instructions under 'to mount a disk:'
 
  sudo /bin/mount /dev/sdd1 ~/data1
 
for other than root to be able to write to the disk, do this
 
  sudo mkdir ~/data1/user
  sudo chmod a+rwx ~/data1/user
 
you should now see something like this
 
  ls -l ~/data1
  total 20
  drwx------. 2 root root 16384 Jun 11 11:04 lost+found/
  drwxrwxrwx. 2 root root  4096 Jun 11 11:30 user/
 
and anyone can write to '~/data1/user'. now unmount again as
 
  sudo /bin/umount /dev/sdd1
 
 
==Setting up Sudo==


reminder for system managers regarding how sudo is set up for the above procedures to work
reminder for system managers regarding how sudo is set up for the above procedures to work

Latest revision as of 15:31, September 20, 2021

These are (terse) write-ups of how to mount/unmount, as well a format disks, on the gs and dgs machines using the ESATA interface (works for usb as well).

To mount a Disk

power disk up and type 'dmesg' to see what device name the computer chose. You should see something like this at the bottom of the list: (NOTE: it may take a little while before the disk is recognized!!)

.
.
.
[1624926.943952] usb 2-1: Product: STORE N GO
[1624926.943954] usb 2-1: Manufacturer: Verbatim
[1624926.943956] usb 2-1: SerialNumber: 07A3130929761542
[1624926.944802] scsi22 : usb-storage 2-1:1.0
[1624927.978847] scsi 22:0:0:0: Direct-Access     Verbatim STORE N GO       5.00 PQ: 0 ANSI: 0 CCS
[1624927.983253] sd 22:0:0:0: Attached scsi generic sg8 type 0
[1624928.496834] sd 22:0:0:0: [sdd] 7827456 512-byte logical blocks: (4.00 GB/3.73 GiB)
[1624928.498952] sd 22:0:0:0: [sdd] Write Protect is off
[1624928.498955] sd 22:0:0:0: [sdd] Mode Sense: 03 41 00 00
[1624928.501080] sd 22:0:0:0: [sdd] No Caching mode page present
[1624928.501084] sd 22:0:0:0: [sdd] Assuming drive cache: write through
[1624928.508574] sd 22:0:0:0: [sdd] No Caching mode page present
[1624928.508577] sd 22:0:0:0: [sdd] Assuming drive cache: write through
[1624928.530109]  sdd: sdd1
[1624928.535695] sd 22:0:0:0: [sdd] No Caching mode page present
[1624928.535698] sd 22:0:0:0: [sdd] Assuming drive cache: write through
[1624928.535701] sd 22:0:0:0: [sdd] Attached SCSI removable disk
[1624928.869338] SELinux: initialized (dev sdd1, type vfat), uses genfs_contexts
[1625347.268862] SELinux: initialized (dev sdd1, type vfat), uses genfs_contexts

or use

 lsblk

to see what disks are there. Not all systems have this handy utility.

then do

 sudo e2label /dev/sdd1

to see if the disk has an identifying label (see how to give a partition an identifying label below); which you can then use as

 mkdir ~/esata/`sudo e2label /dev/sdd1`
 sudo /bin/mount /dev/sdd1 ~/esata/`sudo e2label /dev/sdd1`
 lsblk
 df | grep `sudo e2label /dev/sdd1`


To Unmount the Disk Again

 sync;sync;sync
 sudo /bin/umount /dev/sdd1

If you cannot unmount the disk, make sure you (or someone else) have not cd'ed to the disk in some window somewhere. Sometimes 'lsof | grep cwd' is useful in order to reveal who is cd'ed to the disk


Trouble Unmounting a USB Disk

Sometimes a user has cd'ed to a USB disk in some window (shell) and then if someone else tries to unmount the disk they will get a message like this:

 umount: /media/120514a: umount failed: Operation not permitted

The solution is to find the offending process and kill it cold. If the disk is labeled '120514a', then the steps are:

  lsof | grep 120514a

you might see something like this

 bash       8367       dgs  cwd       DIR       8,49    20480   61341743 /media/120514a/user/cs

you can now kill this offending process as

  kill -9 8367

and then you can do

  umount /media/120514a

To Format a Disk

WARNING: do not format the wrong disk, our you could get into big trouble!! If you are uncertain about how to format a disk, it is best to ask for help.

follow the procedure under 'to mount a disk:' to find the device name. Here we will assume '/dev/sdd'

partition the disk using fdisk:

 sudo /sbin/fdisk /dev/sdd

typically, for a new disk, you would simply say:

 p
 n
 p
 1
 hit return for default
 hit return for default
 w

this will create the partition '/dev/sdd1' which we will now impose a linux EXT4 file system on as

sudo /sbin/mkfs.ext4 -m 0 /dev/sdd1

to be able to write to the 5% of the disk that is normally reserved for root. For a data disk this is OK, but for a system disk it is a bad idea.

On some machines this takes a long time (e.g., scientific linux) , on others it is very fast (e.g., fedora 15)

It is a good idea to give the disk a UNIQUE label that makes sense to you, maybe just the date and a serial character:

 sudo /sbin/e2label /dev/sdd1  20120611a

With this label, if this disk is mounted automatically as a usb disk, it will then come up as /media/20120611a

You can now mount the disk using the instructions under 'to mount a disk:'

 sudo /bin/mount /dev/sdd1 ~/data1

for other than root to be able to write to the disk, do this

 sudo mkdir ~/data1/user
 sudo chmod a+rwx ~/data1/user

you should now see something like this

 ls -l ~/data1
 total 20
 drwx------. 2 root root 16384 Jun 11 11:04 lost+found/
 drwxrwxrwx. 2 root root  4096 Jun 11 11:30 user/

and anyone can write to '~/data1/user'. now unmount again as

 sudo /bin/umount /dev/sdd1


Setting up Sudo

reminder for system managers regarding how sudo is set up for the above procedures to work


visudo

 Cmnd_Alias ESATAFORMAT = /sbin/e2label, /sbin/fdisk, /sbin/mkfs.ext4, /bin/mkdir, /bin/chmod
 gamuser ALL=ESATAFORMAT
 dgs     ALL=ESATAFORMAT
 Cmnd_Alias ESATAMOUNT = /bin/mount, /bin/umount
 gamuser ALL=ESATAMOUNT
 dgs     ALL=ESATAMOUNT

your system manager may or may not be friendly enough to let you do this...