Topics: Backup & restore, Spectrum Protect

Check Spectrum Protect / TSM backups

An easy command to check on the Spectrum Protect / TSM server what the backup status of all the Spectrum Protect / TSM clients is using the "q event" command. For example:

q event * * begind=-1 begint=09:00 endd=today endt=09:00
The command above will display the status of all the backups jobs in the last 24 hours between 9 AM yesterday and 9 AM today.

Topics: Backup & restore, Spectrum Protect

Spectrum Protect / TSM: Display deduplicaton bytes pending removal

There are numerous show commands available for IBM Spectrum Protect / TSM, that will display information about the environment. Many of them aren't as well documented, probably because IBM intends to use these commands for their own support.

Quite a lot of these commands have been documented by Spectrum Protec / TSM users, and an example can be found on the following web site: http://www.mm-it.at/de/TSM_Show_Commands.html.

A very interesting show command, that can be used to display the amount of deduplicate bytes pending removal, is the following command:

tsm: TSM>show deduppending file_disk
ANR1015I Storage pool FILE_DISK has 7,733,543,532,121 duplicate bytes pending removal.
The command above shows the number of byes for storage pool "FILE_DISK" still to be removed by the dedupe processes.

The command may take quite some time to run, up to 10 minutes, so please be patient when issuing this command.

Topics: LVM, Red Hat, Storage

Logical volume snapshot on Linux

Creating a snapshot of a logical volume, is an easy way to create a point-in-time backup of a file system, while still allowing changes to occur to the file system. Basically, by creating a snapshot, you will get a frozen (snapshot) file system that can be backed up without having to worry about any changes to the file system.

Many applications these days allow for options to "freeze" and "thaw" the application (as in, telling the application to not make any changes to the file system while frozen, and also telling it to continue normal operations when thawed). This functionality of an application can be really useful for creating snapshot backups. One can freeze the application, create a snapshot file system (literally in just seconds), and thaw the application again, allowing the application to continue. Then, the snapshot can be backed up, and once the backup has been completed, the snapshot can be removed.

Let's give this a try.

In the following process, we'll create a file system /original, using a logical volume called originallv, in volume group "extern". We'll keep it relatively small (just 1 Gigabyte - or 1G), as it is just a test:

# lvcreate -L 1G -n originallv extern
  Logical volume "originallv" created.
Next, we'll create a file system of type XFS on it, and we'll mount it.
# mkfs.xfs /dev/mapper/extern-originallv
# mkdir /original
# mount /dev/mapper/extern-originallv /original
# df -h | grep original
/dev/mapper/extern-originallv 1014M   33M  982M   4% /original
At this point, we have a file system /original available, and we can start creating a snapshot of it. For the purpose of testing, first, create a couple of files in the /original file system:
# touch /original/file1 /original/file2 /original/file3
# ls /original
file1  file2  file3
Creating a snapshot of a logical volume is done using the "-s" option of lvcreate:
# lvcreate -s -L 1G -n originalsnapshotlv /dev/mapper/extern-originallv
In the command example above, a size of 1 GB is specified (-L 1G). The snapshot logical volume doesn't have to be the same size as the original logical volume. The snapshot logical volume only needs to hold any changes to the original logical volume while the snapshot logical volume exists. So, if there are very little changes to the original logical volume, the snapshot logical volume can be quite small. It's not uncommon for the snapshot logical volume to be just 10% of the size of the original logical volume. If there are a lot of changes to the original logical volume, while the snapshot logical volume exists, you may need to specify a larger logical volume size. Please note that large databases, in which lots of changes are being made, are generally not good candidates for snapshot-style backups. You'll probably have to test in your environment if it will work for your application, and to determine what a good size will be of the snapshot logical volume.

The name of the snapshot logical volume in the command example above is set to originalsnapshotlv, using the -n option. And "/dev/mapper/extern-originallv" is specified to indicate what the device name is of the original logical volume.

We can now mount the snapshot:
# mkdir /snapshot
# mount -o nouuid /dev/mapper/extern-originalsnapshotlv /snapshot
# df -h | grep snapshot
/dev/mapper/extern-originalsnapshotlv 1014M   33M  982M   4% /snapshot
And at this point, we can see the same files in the /snapshot folder, as in the /original folder:
# ls /snapshot
file1  file2  file3
To prove that the /snapshot file system remains untouched, even when the /original file system is being changed, let's create a file in the /original file system:
# touch /original/file4
# ls /original
file1  file2  file3  file4
# ls /snapshot
file1  file2  file3
As you can see, the /original file system now holds 4 files, while the /snapshot file system only holds the original 3 files. The snapshot file system remains untouched.

To remove the snapshot, a simple umount and lvremove will do:
# umount /snapshot
# lvremove -y /dev/mapper/extern-originalsnapshotlv
So, if you want to run backups of your file systems, while ensuring no changes are being made, here's the logical order of steps that can be scripted:
  • Freeze the application
  • Create the snapshot (lvcreate -s ...)
  • Thaw the application
  • Mount the snapshot (mkdir ... ; mount ...)
  • Run the backup of the snapshot file system
  • Remove the snapshot (umount ... ; lvremove ... ; rmdir ...)

Topics: Red Hat, Virtualization

Renaming a virtual machine domain with virsh

There is no API to accomplish renaming a domain (or system) using virsh. The well known graphical tool "virt-manager" (or "Virtual Machine Manager") on Red Hat Enterprise Linux therefore also does not offer the possibility to rename a domain.

In order to do that, you have to stop the virtual machine and edit the XML file as follows:

# virsh dumpxml machine.example.com > machine.xml
# vi machine.xml
Edit the name between the name tags at the beginning of the XML file.

When completed, remove the domain and define it again:
# virsh undefine machine.example.com
# virsh define machine.xml

Topics: Red Hat

Red Hat Enterprise Linux links

Official Red Hat sites:

Other Red Hat related sites:

Topics: Red Hat

Red Hat Customer Portal

Access Red Hat Customer Portal at https://access.redhat.com

  • Access everything provided with subscription in one location:
    • Search knowledge-base for solutions, FAQs, and articles.
    • Access official product documentation.
    • Submit and manage support tickets.
    • Attach and detach product subscriptions.
    • Download software, updates, and evaluations.
  • Parts of site accessible to everyone.
    • Other parts are exclusive to customers with active subscriptions.
  • Get help with Customer Portal at https://access.redhat.com/help/
Note: The Red Hat Customer Portal can be accessed via command line tool:
# redhat-support-tool
Welcome to the Red Hat Support Tool.
Command (? for help):
You can access it from any terminal or SSH connection, and you can use it as interactive shell (which is default) or execute individual commands with options and arguments. The syntax is identical for both methods. To see all available commands, use "help".

Topics: Red Hat, Security

Generating random passwords

A way to create a random password yourself is using a password generator. The pwmake is a command-line tool for generating random passwords that consist of all four groups of characters: uppercase, lowercase, digits and special characters.

The utility allows you to specify the number of entropy bits that are used to generate the password. The entropy is pulled from /dev/urandom. The minimum number of bits you can specify is 56, which is enough for passwords on systems and services where brute force attacks are rare. 64 bits is adequate for applications where the attacker does not have direct access to the password hash file (/etc/shadow). For situations when the attacker might obtain the direct access to the password hash or the password is used as an encryption key, 80 to 128 bits should be used. If you specify an invalid number of entropy bits, pwmake will use the default of bits.

To create a password of 128 bits, enter the following command:

# pwmake 128
*oLhezv@Hal7YmUM;Igqilur0N&

Topics: Backup & restore, Spectrum Protect

IBM Spectrum Protect/TSM Links

Official IBM Spectrum Protect / Tivoli Storage Manager sites:

Other TSM related sites: IBM Spectrum Protect

Topics: AIX

AIX Links

Links / URLs regarding IBM AIX:

Topics: Backup & restore, Spectrum Protect

Start a backup from the TSM / IBM Spectrum Protect server

There is a way to start a backup from the TSM / IBM Spectrum Protect server itself, and that is by defining a client action. For example, to start an incremental backup on a node, run:

define clientaction action=incremental
You can use wild cards like * in the node name, for example:
def clienta node* act=i
You can monitor the schedule event, using the following command:
q ev * @1
You may cancel this schedule, by running:
delete schedule @1

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