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Compressed data

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by dzone

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We currently have a dead hardrive which had Novell on it. The hardrive had been compressed and then un-compressed, so when we tried to use the back up data from the tapes some of the files were corrupted. Doing some research we discoverd that it wasdue to it being on a Novel compressed drive. So I wanted to know does anyone now how to fix compressed data. I.E. xls. doc. mdb.

9 replies

by cpucardiologist

Maybe too late, but you can checkout Novell's TID 2925087 for some troubleshooting help.

Novell uses a proprietary compression algorithm for file compression. I have not seen the problems using NetWare compression, but I have to admit that I do not have that many sites usnig it. Subblock allocation yes, compression, no.

Good luck!

by rwscc

You shouldn't have a compression problem restoring the files from a good backup tape. the only problem I've seem is files not being backed up because there wasn't sufficient free space to decompress the file. If your dead hard drive had the sys volume on it, be sure to rebuild sys to the same patch level as the original before you install the backup software and restore from tape. I have had corrupt files during a restore because the rebuilt system was two patch levels behind the system that had done the backup. (Also be sure you have the C:\nwserver directory up to the same patch level as the sys volume.)
I agree with the other answer that Novell's compression isn't worth using. Because of the required free space on a volume to decompress when needed, the improvement in data capacity on a volume is little to none.

by rogerndgreen

As well as your later posting, I've now seen this one which has a bit more info on it.
In addition to the other comments, something I have found is that if data is backed up from a drive that had compression enabled, you cannot restore it (at leastwith Backup exec you can't) to a drive that is not compressed. (Yeah, compression was a mistake made when the server was built....).

What you may well need to do (assuming your tape is good) is to create an additional volume (with compression enabled) and restore the files to that volume. THEN copy the files from the temporary volume to the required volume (which doesn't have compression enabled).
Like I dsaid, I agree with the other two comments about not using Novell's compression on a volume (and under 4.11 I believe it was actually turned on by default).
Roger

by ole_ethernets

You will probably need to set up a new NetWare server, then add the questioned NetWare compressed volume as mentioned by the other gentleman. Re-name the volume if it was originally the Sys Volume. Get the volume mounted and working properly with Novell Compression enabled for the volume. Don't disable compression at this point, on a volume which has been compressed. It would be a good idea to then run Vrepair on the volume before trying to copying any files to any other volume. If NetWare detects a problem with the volume fat tables and things, it will automatically run Vrepair when you reboot the server. NetWare volumes are version reverse compatible to a point, i.e.version 4.0 and up. Vrepair should repair any volume errors to it's original compressed state, provided the hardware is still OK.

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