Limit to saveset names on tape?

[Bill Steinborn]

Is there a limit to the length of a saveset name on tape?
If so, what is it and is there a workaround?


I built a menu-driven backup/restore system for our Alpha/VMS cluster. I tested it using backups to disk (for speed). Everything worked, and the system depends on saveset names containing certain information.

Today we started testing with tape and encounteed warnings where the saveset names exceeded 17 or 18 characters. Then BACKUP truncated the saveset names to about 17 characters.

My script message:
Backing up $1$DKE200:[SYSDATAP...]* to MKB200:$1$DKE200_SYSDATAP_092904.BCK (incremental since YESTERDAY)

Backup said:
%BACKUP-I-SSNAMTRUNC, save-set name too long, truncated to $1$DKE200_SYSDATA

[labadie_1]

I see
SSNAMTRUNC, save-set name too long, truncated to 'save-set-name'


Facility: BACKUP, Backup Utility
Explanation: The specified label exceeds the maximum length and was truncated to the legal limit of 6 characters.
User Action: Specify a volume label with 6 or fewer characters.

at http://h71000.www7.hp.com/doc/73final/6023/6023pro_016.html

what is the label name ? Could you add /ign=label to your command ?

[Bojan Nemec]

Hi,

According to the documentation
http://h71000.www7.hp.com/doc/73final/6023/6023pro_016.html
(and probably HELP/MESSAGE SSNAMTRUNC) the limit is 6 characters. This limit is not for the saveset name but for the tape label.

Backup initializes the tape before write to it (probably you use the /REWIND qualifier). If you initialize the tape with the INITIALIZE command and do the backup without /REWIND but with the /IGNORE=LABEL qualifier, this informational will probably disapear.

The starnge thing that the label is truncated to 17 characters.

Bojan

[Bill Steinborn]

I already ignore the label.
Here is the command it complained about. I inserted some breaks and spaces to make it easier to read.
(Originally written long ago by someone else. I just changes the LIS and SAVE_SET names to provide info to the menu system.)

BACKUP/IGNORE=LABEL/LOG
/LIST=$1$DKE200_SYSDATAP_092904.LIS
/IGNORE=(LABEL,INTERLOCK)

$1$DKE200:[SYSDATAP...]*
/MODIFIED/SINCE=YESTERDAY

MKB200:$1$DKE200_SYSDATAP_092904.BCK
/MEDIA=COMPACT/NOCRC/GROUP=0/BLOCK=65534

As I stated, the very same command works when writing the saveset to disk, instead of tape.

[Bill Steinborn]

Here are the initialize and mount commands before the BACKUP command:

$ INITIALIZE/media=compact 'DEVICE' INCBCK
$ MOUNT/FOREIGN 'DEVICE'

[Jan van den Ende · Accepted solution]

Bill,

your hunch is right on the spot: saveset names on tape DO have a length limit of 16 or 17 chars (can not check exactly now, but I have read it, I think in the Backup documentation).

One way to trick yourself into a little less unfavorable position would be to leave out ".BCK", and replace the "_" before the date by "." .
It only gains you 4 characters, but hey, that's 25%.

It has been helping us for years...


Jan

[Martin P.J. Zinser]

Hello Bill,

try to do a mount/over=id and a dir on the tape. Which results do you get for the label and saveset name?

Greetings, Martin

[Bojan Nemec]

Bill,

Jan is right. Now I found this in documentation
http://h71000.www7.hp.com/doc/731FINAL/4506/4506pro_002.html#103_hdr1label

The file name length limit is 17 characters.

Bojan

[Bill Steinborn]

This is what the LIS file shows. (I am across town from the actual computer. My menus are run by operators, since they have the tape drives.)

Save set: $1$DKE201_092004.
Label: SYSDATAP

[Bill Steinborn]

Jan, thank you.
Your workaround may help. I'll have to rework some things, and hopefully this won't be a roadblock too much longer.

To everyone else, thank you as well.

[Bill Steinborn]

Now that it is confirmed that I am limited to 17 characters, I'll rework the system.

Thanks to all.