Downloading incremental backups

uk01

• October 20, 2017 21:02

Hi, We have just switched over to incremental backups using nfs, which the transfer to a remote server. For the last 8+ years we've downloaded the tars of cancelled or transferred accounts to our office computers for safe keeping or restores in the event they are needed again. (especially those for websites we develop) If we want to create a tar of an account on the backup server, can we just select the date/account we want to tar and via the hardlinks it will create a restorable tar file of that account? Eg if we keep 7 days backups and we select /2017-10-17/username it will create a full tar of how the account was on that day using the hardlinks in the incremental files? Or if we selected the latest backup it would create a full tar of that. If this works, it will of course be MUCH slower as backup servers are low spec high storage, but at least we could get a working tar if we needed one for storage or to give to a customer who wants it. Thanks

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  cPanelMichael

  • October 25, 2017 13:00

  Hello, You'd want to first create the archive itself using the "tar" utility. The following StackOverflow explains how this works when using the "tar" utility: Dereferencing hard links Thank you.

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  uk01

  • October 25, 2017 14:08

  Hi Michael, Thanks, I did some tests on an account with no changed files. First backup /backups/2017-10-23/accountname Downloaded the folder via Cyberduck = 902mb OK - full folder download from first backup Latest backup /backups/2017-10-25/accountname Downloaded the folder via Cyberduck = 902mb OK - so it downloaded all files via the symlinks Tar test First backup /backups/2017-10-23/accountname Tar via Cyberduck to accountname.tar.gz = 788mb OK - full size tar from first backup Latest backup /backups/2017-10-25/accountname Tar via Cyberduck to accountname.tar.gz = 788mb OK - so it created tar via the symlinks SSH tar test tar -zcf accountname.tar.gz /backups/2017-10-23/accounts/whmwork 788mb tar -zcf accountname.tar.gz /backups/2017-10-25/accounts/whmwork 788mb So it seems the tar does follow symlinks ok and creates an archive. You linked me to another article which mentions -h, --dereference follow symlinks; archive and dump the files they point to --hard-dereference follow hard links; archive and dump the files they refer to Which of these and where/why do we need to use them? Thanks

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  cPanelMichael

  • October 27, 2017 17:47

  Hello, You shouldn't need to use them, as you noticed the "tar" command you used should handle it by default. Here's a third-party URL discussing hard links and symlinks: What is a hard link? -- definition by The Linux Information Project (LINFO) Thank you.

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