Solved: Log Backup with DeviceType pipe

Former Member · ‎10-13-2007

hello friends,

i read the tutorial for backup with pipe:

-Log Backup to a Pipe

-Defining a Backup Template for Log Backup to a Pipe

I become the following error on shell in dbmcli:

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dbmcli on N4S>backup_start DemoPipeLog

ERR

-24988,ERR_SQL: Sql error

-903,Host file I/O error,No more devices

17,Servertask Info: because Error in backup task occured

10,Job 1 (Backup / Restore Medium Task) [executing] WaitingT137 Result=3700

6,Error in backup task occured, Errorcode 3700 "hostfile_error"

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On DBMGUI in Backup-History the following error:

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Error: No more devices(-903)

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I think I understand the "pipe" strategy.

Can someone help me to explain this "pipe" strategy.

many thanks,

christoph

markus_doehr2 · ‎10-13-2007

A pipe is a special device file on the operating system.

If you backup to a pipe, you need a program "on the other side of the pipe", that picks the data. I use that mechanism to do system copies:

- create one (or more) pipes on operating system level (on source and target)

mknod /tmp/pipe1 p

- create a backup medium, that writes to the pipe and reads from the pipe on the other system

- start the backup

- take the data out of the pipe and put it on a second pipe on a remote system

dd if=/tmp/pipe1 | rsh <remotesystem> dd of=/tmp/pipe1

- restore the backup on the second system using that pipe

If you are only local you could do

dd if=/tmp/pipe of=<some-file-on-the-filesystem>

There are backup tools (HP Dataprotector, EMC/Legato Networker) that use that mechanism to do backups.

--

Markus

Log Backup with DeviceType pipe