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Does hardware compression still make sense on tape drives, considering the performance of modern CPUs? Also, what should I do if I have some data which is already compressed in GZIP and my drive is working with hardware compression enabled? And, are the hardware compression algorithms proprietary, thus making it impossible to read the tape on a similar but not identical tape drives? Thanks!

Laurent
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As the tape drive has hardware dedicated to compression, your CPU can be used to something else... so yes, it makes sense. On a file server, you want the server to serve the file request, no compressing data for the backup.

Tape drive hardware works "on the fly" ... if you backup some data already compressed as "zip" files, then the compression will likely make a bigger data block, so the drive will store the original data, with no more compression. There's no tuning to do, the drive do it itself. It's all documented in the technical manual.

The compression algorithms are shared through the same kind of drive. All LTO drives can read/write tape written by other manufacturer LTO drive.

Kamy
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  • LTO-DC explicitly doesn't increase the size of already compressed data - no need to turn it off. – Zac67 Nov 25 '22 at 09:36
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For starters, check to see if the data being stored is encrypted. If it is, there's no point doing compression, as encrypted data should not be compressible if it is encrypted properly.

I've found I get better (not necessarily smaller) compression using software, instead of hardware compression. With software compression you can choose what sort of compression you want: highly compressed, or fast, or even lossy (eg jpg). I've found that when doing backups of virtual disks I like to choose different compression depending on available bandwidth of each of the links in the chain. You also need to ask yourself, which is faster, the hardware compression cpu in the drive, or the available capacity of the main cpu of the server?

If maximum compression ratio is needed, software compression usually wins here too, as you can choose which software is used and best matches the data type being compressed.

If you just want everything compressed reasonably, and don't want to have to think too hard about how it's being done, hardware compression may be a viable option.

BeowulfNode42
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Makes sense only when you have a backup copy of it.

Don't do hardware compression if you do not have a backup copy of it.

Max Dax
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  • The point in running a backup is to have a copy of your data. If you don't trust compression you can't use for backup, but you don't say why we shouldn't trust hardware compression. I've been using it for decades (with DAT and LTO) without a single problem. – Zac67 Nov 25 '22 at 09:39