[Top][All Lists]
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [rdiff-backup-users] Tar replacement - format proposal
From: |
John Goerzen |
Subject: |
Re: [rdiff-backup-users] Tar replacement - format proposal |
Date: |
Mon, 29 Sep 2003 14:59:20 -0500 |
User-agent: |
Mutt/1.4i |
On Mon, Sep 29, 2003 at 03:20:48PM -0400, Greg Freemyer wrote:
> Commercial backup software often writes "file marks" on the tape every
> once in a while. (Linux can do this with the mt command. Also tape
> file marks have nothing to do with traditional on disk files, but are a
> unique tape concept.)
FWIW, on Linux, writing a file mark happens automatically when you close()
the fd referring to the tape device. I believe this behavior is common with
other operting systems as well.
> Then tape drives have the ability to move between file marks extremely
> quickly. Apparently they are physically very large and easy for the
> tape drive to register even at very high speed.
True; however, it also complicates things because it's a misuse of what the
file mark is really for. It's really for just that -- marking EOF and
skipping to the desired file on a tape. Many tape drive also have the
ability to quite rapidly seek to a particular block anywhere on the tape,
whether it's at a file mark or not.
> As you say, tar's inability to take advantage of this type of tape
> handling causes it to be extremely slow for partial restores.
Indeed.
- Re: [rdiff-backup-users] Tar replacement - format proposal, (continued)
- Re: [rdiff-backup-users] Tar replacement - format proposal, Greg Freemyer, 2003/09/26
- Message not available
- [rdiff-backup-users] Why Tape, Greg Freemyer, 2003/09/26
- Re: [rdiff-backup-users] Why Tape, Kevin Spicer, 2003/09/26
- Re: [rdiff-backup-users] Why Tape, Ben Escoto, 2003/09/26
- Re: [rdiff-backup-users] Why Tape, David Kempe, 2003/09/29
Re: [rdiff-backup-users] Tar replacement - format proposal, John Goerzen, 2003/09/26
Re: [rdiff-backup-users] Tar replacement - format proposal, Ben Escoto, 2003/09/26
Re: [rdiff-backup-users] Tar replacement - format proposal, John Goerzen, 2003/09/26
Re: [Duplicity-talk] Re: [rdiff-backup-users] Tar replacement - format proposal, Will Dyson, 2003/09/26
[rdiff-backup-users] Re: [Duplicity-talk] Tar replacement - format proposal, Will Dyson, 2003/09/26