[BackupPC-users] Rsynv vs. tar, full vs. incremental
Hi, Incremental backup of a linux machine using tar (i.e. only files newer than...) is several times faster than using rsync. On the other hand, full backup using tar transfers huge amount of data over network, way more than the efficient rsync. Is there a way to use rsync for full backup and tar for the incremental runs? I do not even know whether the two transfer modes formats produce mutually compatible data in the pool. Thanks a lot for any hints. Pavel. -- Simplify data backup and recovery for your virtual environment with vRanger. Installation's a snap, and flexible recovery options mean your data is safe, secure and there when you need it. Data protection magic? Nope - It's vRanger. Get your free trial download today. http://p.sf.net/sfu/quest-sfdev2dev ___ BackupPC-users mailing list BackupPC-users@lists.sourceforge.net List:https://lists.sourceforge.net/lists/listinfo/backuppc-users Wiki:http://backuppc.wiki.sourceforge.net Project: http://backuppc.sourceforge.net/
Re: [BackupPC-users] Rsynv vs. tar, full vs. incremental
Hi, Pavel Hofman wrote on 2011-05-31 15:24:56 +0200 [[BackupPC-users] Rsynv vs. tar, full vs. incremental]: Incremental backup of a linux machine using tar (i.e. only files newer than...) is several times faster than using rsync. that could be because it is missing files that rsync catches. Or perhaps I should rather say: yes, tar is probably more efficient, but it is less exact than rsync, because it only has one single timestamp to go by, whereas rsync has a full file list with attributes for all files. One very real consequence is that tar *cannot* detect deleted files in incremental backups while rsync will. My understanding is that the concept of incremental backups, way back in times where we did backups to tapes, was introduced simply to make daily backups feasible at all. Something along the lines of it's not great, but it's the best we can do, and it's good enough to be worthwhile. Nowadays, incremental backups still have their benefits, but we really need to shake the habit of making compromises for no better reason than that we haven't yet realized that there is an alternative. If you determine that incremental tar backups are good enough for you (e.g. because the cases it doesn't catch don't happen in your backup set), or that your server load forces you to make a compromise, then that's fine. But if it's only tar is faster than rsync and faster is better, then you should ask yourself why you are doing backups at all (no backups is an even faster option). On the other hand, full backup using tar transfers huge amount of data over network, way more than the efficient rsync. There are also other factors to consider like CPU usage. Where exactly is your bottleneck? Is there a way to use rsync for full backup and tar for the incremental runs? No. Actually, *the other way around*, it would make sense: full backups with tar (probably faster than rsync over a fast local network - depending on your backup set) and incremental backups with rsync (almost as exact as a full backup). I do not even know whether the two transfer modes formats produce mutually compatible data in the pool. No. There is (or was?) a slight difference in the attribute files, leading to retransmission of all files on the first rsync run after a tar run (because RsyncP thinks the file type has changed from something to plain file). The rest is, of course, compatible. It would be a shame if pooling wouldn't work between tar and rsync backups, wouldn't it? :) Regards, Holger -- Simplify data backup and recovery for your virtual environment with vRanger. Installation's a snap, and flexible recovery options mean your data is safe, secure and there when you need it. Data protection magic? Nope - It's vRanger. Get your free trial download today. http://p.sf.net/sfu/quest-sfdev2dev ___ BackupPC-users mailing list BackupPC-users@lists.sourceforge.net List:https://lists.sourceforge.net/lists/listinfo/backuppc-users Wiki:http://backuppc.wiki.sourceforge.net Project: http://backuppc.sourceforge.net/
Re: [BackupPC-users] hard links again
Nope - hard links are the essence of BackupPC Scott wrote at about 16:20:37 -0400 on Tuesday, May 31, 2011: Is it possible for backuppc to use symbolic or soft links instead of hard links? I found a seemingly great software FlexRaid which allows me to create a software parity raid using various drives.However, it does not support hard links, only soft! -- -- Simplify data backup and recovery for your virtual environment with vRanger. Installation's a snap, and flexible recovery options mean your data is safe, secure and there when you need it. Data protection magic? Nope - It's vRanger. Get your free trial download today. http://p.sf.net/sfu/quest-sfdev2dev -- ___ BackupPC-users mailing list BackupPC-users@lists.sourceforge.net List:https://lists.sourceforge.net/lists/listinfo/backuppc-users Wiki:http://backuppc.wiki.sourceforge.net Project: http://backuppc.sourceforge.net/ -- Simplify data backup and recovery for your virtual environment with vRanger. Installation's a snap, and flexible recovery options mean your data is safe, secure and there when you need it. Data protection magic? Nope - It's vRanger. Get your free trial download today. http://p.sf.net/sfu/quest-sfdev2dev ___ BackupPC-users mailing list BackupPC-users@lists.sourceforge.net List:https://lists.sourceforge.net/lists/listinfo/backuppc-users Wiki:http://backuppc.wiki.sourceforge.net Project: http://backuppc.sourceforge.net/
Re: [BackupPC-users] hard links again
On 5/31/2011 3:20 PM, Scott wrote: Is it possible for backuppc to use symbolic or soft links instead of hard links? No, it is the atomic nature of kernel hardlink handling that makes what backuppc does possible. I found a seemingly great software FlexRaid which allows me to create a software parity raid using various drives.However, it does not support hard links, only soft! With the price of disks these days it seems like a waste of time to try to accommodate drives that aren't what you need. -- Les Mikesell lesmikes...@gmail.com -- Simplify data backup and recovery for your virtual environment with vRanger. Installation's a snap, and flexible recovery options mean your data is safe, secure and there when you need it. Data protection magic? Nope - It's vRanger. Get your free trial download today. http://p.sf.net/sfu/quest-sfdev2dev ___ BackupPC-users mailing list BackupPC-users@lists.sourceforge.net List:https://lists.sourceforge.net/lists/listinfo/backuppc-users Wiki:http://backuppc.wiki.sourceforge.net Project: http://backuppc.sourceforge.net/
Re: [BackupPC-users] hard links again
I noticed the backup data appears to be stored in the pc directory. Does that mean the hardlinks are in the pool directory and not in the pc directory? So would it be possible to store the pc directory in a different directory (in my flexraid pool) but store the pool directory in a normal ext file system? What about the cpool ? -- Simplify data backup and recovery for your virtual environment with vRanger. Installation's a snap, and flexible recovery options mean your data is safe, secure and there when you need it. Data protection magic? Nope - It's vRanger. Get your free trial download today. http://p.sf.net/sfu/quest-sfdev2dev___ BackupPC-users mailing list BackupPC-users@lists.sourceforge.net List:https://lists.sourceforge.net/lists/listinfo/backuppc-users Wiki:http://backuppc.wiki.sourceforge.net Project: http://backuppc.sourceforge.net/
Re: [BackupPC-users] hard links again
Hi, Scott wrote on 2011-05-31 19:57:11 -0400 [Re: [BackupPC-users] hard links again]: I noticed the backup data appears to be stored in the pc directory. Does that mean the hardlinks are in the pool directory and not in the pc directory? ah, you don't understand what hardlinks are. Hardlinks are simply different names (directory entries) pointing to the same content (inode, file). They're indistinguishable from each other. There's no primary name, they are all equal. The content you access is identical, no matter which of the names you use. If you need more explanation, google is your friend. So would it be possible to store the pc directory in a different directory (in my flexraid pool) but store the pool directory in a normal ext file system? What about the cpool ? No. Hardlinks can obviously only work within one file system. Regards, Holger -- Simplify data backup and recovery for your virtual environment with vRanger. Installation's a snap, and flexible recovery options mean your data is safe, secure and there when you need it. Data protection magic? Nope - It's vRanger. Get your free trial download today. http://p.sf.net/sfu/quest-sfdev2dev ___ BackupPC-users mailing list BackupPC-users@lists.sourceforge.net List:https://lists.sourceforge.net/lists/listinfo/backuppc-users Wiki:http://backuppc.wiki.sourceforge.net Project: http://backuppc.sourceforge.net/
