Max media mounts for LTO4

[RXZrider]

Hi Experts,

I have been facing a issue in our enviroment. A tape which was purchased 6 months back has been written twice but the mounts in NBU Media console is 2512. The last written date is 13 July 2013. As per client policy the max mounts to be used 52. So there's a big question from client side how can a tape show 2512 mounts when used only for 2 backups. I checked the media catalog info and found 253 images last written on 8th and 13th July 2013.

[RiaanBadenhorst]

Just a guess but a mount doesn't necessarily constitute a write or a backup? It could have mounted, and then had an io, or position error. Is it only this one media?

[Mark_Solutions]

So was this tape first introduced into the environment in July or are you assuming that due to its last written date?

It has 253 images on it at the moment so could well have been mounted 253 times since July - if it is older it would only need to have been overwritten 10 times to have 2512 mounts

A few issues or failures during that time and it would soon build up

If you go into the columns layout in the media view you will see that there is a "Created" column

Show this one to see when NetBackup first knew about that tape

Is the tape used for backups or duplications? If backups are they mutiplexed?

[RXZrider]

bash-3.2# vmquery -m 885CES
================================================================================
media ID:              885CES
media type:            1/2" cartridge tape (6)
barcode:               885CES
media description:     Added by Media Manager
volume pool:           Infra_weekly (30)
robot type:            NONE - Not Robotic (0)
volume group:          ---
vault name:            ---
vault sent date:       ---
vault return date:     ---
vault slot:            ---
vault session id:      ---
vault container id:    -
created:               Sat Jun 29 05:49:45 2013
assigned:              Sun Jul 07 15:03:14 2013
last mounted:          Sat Jul 13 22:04:02 2013
first mount:           Thu Jul 04 02:16:00 2013
expiration date:       ---
number of mounts:      2512
max mounts allowed:    ---
status:                0x0
================================================================================

[RXZrider]

A small correction Valid images = 260.

Not multiplexed. Used for only backups and not duplications.

[Mark_Solutions]

What sort if backups are they - just wondering if there could be a reason for so many mounts in such a short period of time

Is it just this tape or are others similar?

Starting to think it is a glitch somewhere that has caused this but there could be other reasons (like a very small STU fragement size combined with lots of jobs running  - especially SQL type backups - and resources getting switched between jobs - usually happens during duplications though)

[StefanosM · Accepted solution]

If the facts are correct, the only possible answer I can think is that if during the backup the drive ask for cleaning tape  (cleaning required) and there was not a cleaning tape inside the library (or with 0 cleanings).

I had seen it many times with netbackup. In this situation netbackup after mount the tape receives the tape alert from the drive, umount the tape and starts from the beginning mounting the same tape again and again.

I just wandering if your customer had ever DAT tapes. The policy to replace the LTO tapes every 52 mounts is very expensive and without any sense. LTO ta5e lifespan is more than 52 mounts
http://portal.archiware.com/support/index.php?/Knowledgebase/Article/View/189/2/lto-tape-durability

I have a customer that has tapes with 40,000 mounts (log backups) and the tapes are still working. (He must replace the tapes)

[RXZrider]

There are a few other tapes where as they can be neglected as they are multiplexed, having 1500+ images and were used for archive backups.

Media ID

Media Type

Media

Status

Last Written

Kilobytes

Data Expiration

Mounts

Time Assigned

Application

Created

First Mount

Last Mount

Images

Valid Images

-----------

-------------

------

------------------------------------------

--------------------

---------------

--------------------

---------

------------

JK0406

HCART

Frozen

0

6723

6/9/2013 5:00

0 - NetBackup

12/16/2009 11:52

12/21/2009 23:05

6/9/2013 5:01

0

0

NJ5982

HCART

Active

Multiplexed

12/11/2013 12:04

1497464996

12/18/2013 12:04

4323

8/21/2013 10:22

0 - NetBackup

2/6/2013 14:53

2/11/2013 9:57

12/11/2013 12:01

3429

3429

NJ5987

HCART

Active

Multiplexed

12/11/2013 7:08

6319350

12/18/2013 7:08

3920

11/30/2013 5:05

0 - NetBackup

2/6/2013 14:53

2/11/2013 9:58

12/11/2013 7:09

8

8

NJ5958

HCART

Frozen

Multiplexed

11/22/2013 11:10

1247162351

11/29/2013 11:10

3646

10/8/2013 3:00

0 - NetBackup

2/6/2013 14:53

2/11/2013 3:50

11/22/2013 11:11

4479

4479

NJ5980

HCART

Full M

ultiplexed

12/10/2013 16:13

2466514854

12/17/2013 16:13

3607

8/18/2013 4:00

0 - NetBackup

2/6/2013 14:53

2/10/2013 14:27

12/10/2013 16:14

5715

5715

BAK189

HCART

Active

0

3299

0 - NetBackup

11/10/2011 17:43

2/1/2013 19:02

11/22/2013 5:27

0

0

BAK139

HCART

Active

Multiplexed

12/11/2013 7:21

1027024938

12/18/2013 7:21

2834

11/15/2013 17:00

0 - NetBackup

12/3/2012 14:53

12/17/2012 13:55

12/11/2013 7:01

2672

2672

885CES

HCART

Full

7/13/2013 21:56

1491436579

7/13/2014 21:56

2512

7/7/2013 15:03

0 - NetBackup

6/29/2013 5:49

7/4/2013 2:16

7/13/2013 22:04

260

260

941CES

HCART

Active

Multiplexed

12/11/2013 10:14

116370695

12/18/2013 10:14

2395

12/6/2013 16:00

0 - NetBackup

6/29/2013 5:49

7/2/2013 14:33

12/11/2013 10:15

215

215

JK3067

HCART

Frozen

0

1519

2/24/2013 14:07

0 - NetBackup

4/26/2010 15:48

5/2/2010 23:02

2/24/2013 14:08

0

0

539CES

HCART

Full

7/20/2013 16:50

1712114753

7/20/2014 16:50

1406

7/20/2013 5:17

0 - NetBackup

6/26/2013 1:40

6/26/2013 5:00

7/20/2013 16:58

195

195

491CES

HCART

Full M

ultiplexed

7/18/2013 23:05

2007942563

7/17/2016 23:27

1402

7/13/2013 14:25

0 - NetBackup

5/20/2013 8:00

5/21/2013 2:20

7/18/2013 23:03

11

11

JK5684

HCART

Active

Multiplexed

12/11/2013 6:59

2163478607

12/18/2013 6:59

1363

2/15/2013 18:01

0 - NetBackup

7/3/2012 14:24

7/4/2012 12:00

12/11/2013 6:55

12924

12924

079CFE

HCART

Full M

ultiplexed

8/3/2013 23:41

2023940952

8/1/2021 23:41

1143

7/5/2013 10:05

0 - NetBackup

6/22/2013 15:57

6/30/2013 20:12

8/3/2013 23:01

17

17

BAK087

HCART

Active

12/2/2013 11:00

904770292

12/30/2013 11:00

1123

6/17/2013 21:00

0 - NetBackup

11/10/2011 17:43

2/6/2013 9:26

12/2/2013 11:01

44

6

[RXZrider]

Hi Stefanos,

Thats what i too suggested that LTO4 can be used 250 to 300 mounts for end to end writes, and using 52 mounts would prove very expensive. However my problem is i can find out the max mounts for the tape and not the max end to end write mounts(overwrites) from NBU.

[Will_Restore]

I never looked that closely before, have a tape that was first used yesterday, has 2 images and 3 mounts. Another first used two days ago has 164 images and 4 mounts. Highest number of mounts currently in the library is 1502.  That tape has been around for a couple of years.

[Mark_Solutions]

Could just be a glitch then but i do see a few tapes even in that small list that are frozen so maybe you are having drive issues that have caused this

In view of the very large number i tend to think it is a glitch to be honest - whether it is worth raising a case i am unsure as the relevant logs have probably been cleared down already

I tend to doubt if you will get to the bottom of this one but di check out why you are getting frozen tapes as that could be the root cause

[mph999]

The number of mounts of a media is pretty useless in determining media condition.

I have had this confirmed by tape experts at Imation.

More important is how the media has been treated - has it been physically moved often, environmental conditions etc ...

Perhaps the most important factor, is if the tape has been 'shoe shined' - that is run at a speed below the minimum streaming speed for the drive.

This causes multiple issues, mainly increased/ accelerated tape wear and can also untension the tape.  If this has happened, physical movement of the tape is more likely to lead to tape edge damage.

Monitoring this is almost impossible with any backup appliacation - you need specialist tape / drive monitoring software.

[StefanosM]

I still beleave that you had problems with the cleaning tapes (or drive problems) during that time window.