AIX

I am trying to find a way to do the following on an AIX 4.2 with Korn:

tar cvfpdl - . | compress > /dev/rmt0

The /dev/rmt0 is the device we use when we tar directly to it.

I want to compress a folder's content to tape. Our current TAR does not have compression at all. We only have 'compress' as compression command.

When I use the command above, it shows it started to TAR some files but then it failes with a message:
A system call received a parameter that is not valid.


Also, I read there is a GNU tar with compression but do not know if it would work on an 4.2 AIX

Please refer to
AIX 4.2: tar using compression ?

I started that thread.

==> My client has AIX 4.2 !

That does not use compression.


What I am trying to achieve is backing up to tape any folders containing backup files, using compression, not using the current folder as temporary storage (no space for it). All this on an AIX 4.2 who's TAR does not have any compression on it and where I only have 'compress' as compression tool (althougth I said we had gzip, it is not on all our server and I am almost on a deadlock situation when talking to my team lead about copying it to all our servers because he says the license is only on one server !!!)

We have 10 backup disk folders (totalling anywhere between 60-90Gb) on 5 servers (2 DB per servers), each with one single tape drive. The current procedure to do this takes almost 12 hours to do !!!!!!!!! I want to reduce them all to less then 8 hours by using compression (just compression a 1.9Gb file on disk takes 25 min !).

Using pipes you don't need temporary diskspace and tar does not care whether it writes an archive onto disk or onto /dev/rmtX directly. This is all files to Unix. Try to use a combination of commands, pipes and files to backup compressed data onto a tape. Sth. like

Code:

# tar -cBf - /yourdirectory | compress | dd of=/dev/rmt0

B option (blocking) is recommended with pipes. Reverse the syntax to read data from tape again.

Code:

# dd if=/dev/rmt0 | uncompress | tar -xBf -

gzip is open source. What did you mean with "the license is only on one server"?

Doesn't 'compress' use the current folder to store the *.Z files ? If so I cannot do that (sorry I am mistaken. My Unix knowledge is limited). The folders where the backups are are over 90% full. I tried finding other places to move the files (and then compress them) but I did not have enough time to continue my search. Compression will have to be elsewhere (if there is room enough somewhere). The biggest backup folder has 10.5Gb and by extrapolating the compression time, it would take 2hrs to compress the whole thing on disk (I would not gain any time with this way. That is why I am looking for compressing directly to tape). This particular backup folder takes over 4 hours to be TARed to tape (without compression).

By "the license is only on one server", my teamlead said the licence for the few servers (1-2) we have GZIP on them is only valid those servers only ant that it cannot be copied on any other servers. Frankly I do not know if he is telling the truth or simply not knowing the answer at all. We have gzip v1.2.4 on those AIX 4.2 servers (they all have AIX 4.2). I sent an email to the gzip support for the whereabouts of the licence vs our intented usages.

That depends. By using a pipe you redirect the standard output (stdout) of one program to another directly. I.e. the data is not passed through a temporary file. The other program takes the data in via standard input (stdin) from the pipe. This second program may then produce output which again can be redirected into another pipe and so on. I think you got the picture.

What you write about gzip confuses me. Either we are talking about two different programs that have the same name or there is some severe misunderstanding on what "Open Source" software is. In the second case you might point your "teamlead" to the corresponding wikipedia entry.