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On Sunday, 26 September 2021 13:25:24 BST Ramon Fischer wrote: |
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> Addendum: |
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> |
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> To complete the list. Here the parallel implementation of "lzip": |
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> |
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> "plzip": https://www.nongnu.org/lzip/plzip.html |
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> |
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> -Ramon |
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> |
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> On 26/09/2021 14:23, Ramon Fischer wrote: |
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> > In addition to this, you may want to use the parallel implementations |
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> > of "gzip", "xz", "bzip2" or the new "zstd" (zstandard), which are |
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> > "pigz"[1], "pixz"[2], "pbzip2"[3], or "zstmt" (within package |
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> > "app-arch/zstd")[4] in order to increase performance: |
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> > |
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> > $ cd <path_to_mounted_backup_partition> |
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> > $ for tar_archive in *.tar; do pixz "${tar_archive}"; done |
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> > |
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> > -Ramon |
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> > |
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> > [1] |
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> > * https://www.zlib.net/pigz/ |
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> > |
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> > [2] |
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> > * https://github.com/vasi/pixz |
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> > |
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> > [3] |
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> > * https://launchpad.net/pbzip2 |
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> > * http://compression.ca/pbzip2/ |
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> > |
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> > [4] |
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> > * https://facebook.github.io/zstd/ |
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> > |
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> > On 26/09/2021 13:36, Simon Thelen wrote: |
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> >> [2021-09-26 11:57] Peter Humphrey <peter@××××××××××××.uk> |
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> >> |
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> >>> part text/plain 382 |
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> >>> Hello list, |
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> >> |
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> >> Hi, |
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> >> |
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> >>> I have an external USB-3 drive with various system backups. There |
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> >>> are 350 .tar |
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> >>> files (not .tar.gz etc.), amounting to 2.5TB. I was sure I wouldn't |
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> >>> need to |
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> >>> compress them, so I didn't, but now I think I'm going to have to. Is |
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> >>> there a |
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> >>> reasonably efficient way to do this? I have 500GB spare space on |
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> >>> /dev/sda, and |
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> >>> the machine runs constantly. |
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> >> |
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> >> Pick your favorite of gzip, bzip2, xz or lzip (I recommend lzip) and |
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> >> then: |
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> >> mount USB-3 /mnt; cd /mnt; lzip * |
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> >> |
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> >> The archiver you chose will compress the file and add the appropriate |
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> >> extension all on its own and tar will use that (and the file magic) to |
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> >> find the appropriate decompresser when you want to extract files later |
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> >> (you can use `tar tf' to test if you want). |
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|
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Thank you both. Now, as it's a single USB-3 drive, what advantage would a |
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parallel implementation confer? I assume I'd be better compressing from |
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external to SATA, then writing back, or is that wrong? |
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|
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Or, I could connect a second USB-3 drive to a different interface, then read |
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from one and write to the other, with or without the SATA between. |
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|
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-- |
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Regards, |
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Peter. |
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