Re: Compressing backup file
- From: "David J. Dachtera" <djesys.nospam@xxxxxxxxxxxxxxxxxxxxxx>
- Date: Mon, 08 May 2006 18:45:13 -0500
Kevin Handy wrote:
VMS 5.5-2, MicroVax 3100, 8Mb RAM.
Yes, it's an old machine, but it works fine for what it
is doing.
I am looking at creating a backup file, then compressing
it, copying it to a PC, and burning it to a CD.
The test savesets I'm playing with are in the 200,000
to 400,000 block size. Real ones would likely be larger.
Yes, I could put a CD burner on the VAX, but at this stage
I'm looking at generating the data first, and where the
burner is located isn't my problem yet. Generating the
backup sets in a reasonable time is my current problem.
This is for making periodic permanent backups.
They are currently using tape (various TLZ???)
but having serious reliability problems (dust, etc.)
The backup images will be too big to fit on a CD without
compressing them, and moving them to a PC would lose
file attributes.
I am able to do this on the VAX using 'zip "-V" ...', but
it is very, very, very slow. I'd guess it's at least 10X
slower than creating the original backup saveset (I've only
let it run for 2 hours before giving up on a test saveset).
I'm not sure the process would finish overnight.
Zipping the individual files seems to be faster, but
still very slow.
I could copy the uncompressed saveset to a windows PC and
do the compression there, but wouldn't be able to automate
it, and I would lose file attributes. I really want to run
this as an overnight process with the resulting files
available to burn in the morning, and the less the user
needs to work the better (the easier it is to do, the
more often it is likely to get done).
Anyone familiar with doing compression on the a VAX, with
regards to the speed? Would gzip or bzip2 be better/faster
(which would probably lose attributes)?
Any options/discussions?
About all I can add is that the compression process is very CPU
intensive. VAXes always seems to be rather slower than Alpha for this.
I'd be inclined to take Eberhard's advice and write stuff out to DVD
recordable. That may still take awhile, but...
--
David J Dachtera
dba DJE Systems
http://www.djesys.com/
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- From: Kevin Handy
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