Re: [BackupPC-users] BackupPC 3.x Pool on BTRFS?
Christian, I've run BackupPC on zfs for several years. As you point out there is a lot of overlap between the features of BackupPC and COW file systems. However, BackupPC is not designed to take advantage of COW filesystems specifically. My observations: 1. I saw minimal benefit from zfs deduplication when backing up desktop machines. It seems that BackupPC's hard-link based dedupe get's most of available benefit, with very little duplicated data for zfs to do dedupe on. Also with zfs anyway dedupe doesn't work well, and is widely discouraged. I've no experience with dedupe on btrfs. 2. Using filesystem compression instead of BackupPC compression works fine for me. I haven't really compared it to using BackupPC compression. You only want one compression system though. If you use BackupPC compression, your file system compression should be off and if you use the filesystem's compression BackupPC's compression should be off. 3. I've not done physical pool migration, but zfs send can do some cool things. Presumably btrfs send can do similar things. 4. COW filesystems have stability advantages in terms of checksums and the possibility to recover from a snapshot if you make a mistake. They also can have performance problems due to the large number of seeks that can be needed as the file system fragments. It becomes a personal decision as to what you want to use. If you are doing this for a production set up I'd recommend using a filesystem you are comfortable and confident with. Learning BackupPC and a new filesystem could become an adventure ;-) RP On 14/02/16 04:01, Christian Völker wrote: > Hi all, > > I did find only a single reference to the topic- but already some years ago. > > So are there any implications someone need to take care of when using > BackupPC pool on a BTRFS filesystem? > > Some features of BTRFS seems to be perfect for BackupPC but I am unsure > if they have advantages. > > Deduplication feature: > BackupPC hadrlinks identical files to save storage space which is > already deduplication. But it uses hardlinks to do so- which frequently > causes issues as you can see in this mailing list. So possibly diasble > hardlinking in BackupPC (if possible) and let BTRFS do the work with > deduplication? Disadvantage for BTRFS: it is only a "out-of-band" > deduplication- so you have to perform the dupe detection by cron or so. > > Online-Compression: > BTRFS uses online-compression- I am unsure if there would be an > advantage if compression is done by filesystem. At least IMHO it would > be easier to restore directly from the pool instead of cpool through bash? > > Pool-migration/ move: > If you decide to move your pool to a different location you are happy if > you have it on something like LVM (or completely virtualized). Then you > can move the underlying device. Disadvantage: LVM and other tools move > the full device. If the pool is just filled up to 70% it even transfers > the 30% of empty space. With btrfs receive and btrfs send the filesystem > will only transfer the used blocks. > > COW-Feature: > With copy-on-write btrfs writes changed block on a different location > and then refers to this new location. Has advantages for snapshots and > so on. But disadvantages for larger files (like virtual disk images) as > they spread among all devices which causes lots of seeks on rotating > devices like HDDs. How about pool? Am I right this does not matter for > backupPC as it always writes full files only? Even rsync-based backups? > > Besides of BackupPC someone havving experiences in using BTRFS? > > Thanks! > > Christian > > > > > > > -- > Site24x7 APM Insight: Get Deep Visibility into Application Performance > APM + Mobile APM + RUM: Monitor 3 App instances at just $35/Month > Monitor end-to-end web transactions and take corrective actions now > Troubleshoot faster and improve end-user experience. Signup Now! > http://pubads.g.doubleclick.net/gampad/clk?id=272487151=/4140 > ___ > 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/ -- Site24x7 APM Insight: Get Deep Visibility into Application Performance APM + Mobile APM + RUM: Monitor 3 App instances at just $35/Month Monitor end-to-end web transactions and take corrective actions now Troubleshoot faster and improve end-user experience. Signup Now! http://pubads.g.doubleclick.net/gampad/clk?id=272487151=/4140 ___ 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:
[BackupPC-users] BackupPC daemon crashes often
I have a BackupPC server running in a jail on FreeBSD 10. The system mostly works, but recently I've noticed that the BackupPC parent process is frequently needing to be restarted. I even went to the length of having a cron job that checks for the existence of the 'BackupPC -d' process and restarts BackupPC if it's missing. Examining the logs shows the daemon exiting with: Got signal PIPE... cleaning up each time. Has anyone seen this sort of thing, or perhaps have ideas on how I can debug it? Finding the PID of the process than sent the signal is not easy in Perl, but maybe there is some other approach? Thanks Russ Poyner -- Site24x7 APM Insight: Get Deep Visibility into Application Performance APM + Mobile APM + RUM: Monitor 3 App instances at just $35/Month Monitor end-to-end web transactions and take corrective actions now Troubleshoot faster and improve end-user experience. Signup Now! http://pubads.g.doubleclick.net/gampad/clk?id=267308311=/4140 ___ 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/
[BackupPC-users] rsync 3.09 fails on windows symlinkd
I've been using a powershell script to create shadow copies and link them to the filesystem in order to expose them to rsyncd. This works with my oldish copy of DeltaCopy rsync, but when I use the current cygwin-rsync package from the BackupPC web site I'm not able to follow the link. If I tell it to follow the link: rsync -r -L rsyncuser@host::shadow symlink has no referent: C (in shadow) drwxr-xr-x 0 2014/09/17 11:32:30 . rsync error: some files/attrs were not transferred (see previous errors) (code 23) at main.c(1538) [generator=3.0.9] If I don't tell it to follow the link: rsync -r behdadrs...@cbe-win7amd64.che.wisc.edu::shadowdrwxr-xr-x 0 2014/09/17 11:37:30 . lrwxrwxrwx 54 2014/09/17 11:37:30 C On the windows side: dir c:\shadow 09/17/2014 09:27 AM SYMLINKD C [\\?\GLOBALROOT\Device\HarddiskVolume I have use chroot = no in rsyncd.conf I've also tried a variety of links related switches on the rsync client. Googling symlink has no referent: windows turns up a few other people with this problem Anyone been able to solve this one? Thanks Russ Poyner -- Want excitement? Manually upgrade your production database. When you want reliability, choose Perforce Perforce version control. Predictably reliable. http://pubads.g.doubleclick.net/gampad/clk?id=157508191iu=/4140/ostg.clktrk ___ 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/
[BackupPC-users] signal to Kill DumpPreUserCmd
I have a bash script that runs on the BackupPC server as DumpPreUserCmd.
I'd like to have the script catch a signal and clean up it's files if a
backup get's canceled while the script is running. So far I'm trapping
INT, TERM, ABRT and ALRM but not getting what I want.
Does BackupPC send SIGKILL to the DumpPreUserCmd process? Or something
else I haven't thought of?
The value of $Conf{UserCmdCheckStatus} seems to not matter.
Background:
This is in the context of a method to create shadow copies and start
rsyncd on windows clients without having to remotely execute anything on
the windows box via ssh or winexe.
1. The server starts our DumpPreUserCmd bash script which creates a file
called hostname.html in a web-readable directory. It then polls the
windows machine to see if rsyncd has started. Once windows starts it's
rsyncd the PreUser script exits so that the dump can start.
2. The windows machine runs a script in task_scheduler every 5 minutes
to see if the file hostname.html exists in the special directory on
the BackupPC web server. If it does the windows box runs a powershell
script that creates shadow copies, starts rsyncd and opens a firewall
hole to allow the backup.
3. On the server when the dump completes DumpPostUserCmd runs and
removes the hostname.html file.
4. When the periodic task on the windows machine no longer finds the
hostname.html file it stops the rsyncd service, deletes the shadow
copies, and closes the firewall hole.
It works fine unless the backup get's interupted while DumpPreUserCmd is
running and waiting for windows to start it's rsyncd service. In that
case the hostname.html file get's orphaned.
I *could* create a cron job on the server to look for and remove
orphaned hostname.html files, but I'm hoping to not need that.
Thanks
Russ Poyner
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Re: [BackupPC-users] signal to Kill DumpPreUserCmd
PIPE
Seems to be the answer. Adding PIPE to the list of signals trapped by
the script causes it to clean up on exit when the job is killed from the
web interface.
trap cleanup ; trap - INT ; kill -INT $$ INT
trap cleanup ; exit $? TERM ABRT ALRM PIPE
is the snippet that works. cleanup is a function that removes the
hostname.html file and returns an appropriate error value.
Russ Poyner
On 07/24/14 14:36, Russell R Poyner wrote:
I have a bash script that runs on the BackupPC server as DumpPreUserCmd.
I'd like to have the script catch a signal and clean up it's files if a
backup get's canceled while the script is running. So far I'm trapping
INT, TERM, ABRT and ALRM but not getting what I want.
Does BackupPC send SIGKILL to the DumpPreUserCmd process? Or something
else I haven't thought of?
The value of $Conf{UserCmdCheckStatus} seems to not matter.
Background:
This is in the context of a method to create shadow copies and start
rsyncd on windows clients without having to remotely execute anything on
the windows box via ssh or winexe.
1. The server starts our DumpPreUserCmd bash script which creates a file
called hostname.html in a web-readable directory. It then polls the
windows machine to see if rsyncd has started. Once windows starts it's
rsyncd the PreUser script exits so that the dump can start.
2. The windows machine runs a script in task_scheduler every 5 minutes
to see if the file hostname.html exists in the special directory on
the BackupPC web server. If it does the windows box runs a powershell
script that creates shadow copies, starts rsyncd and opens a firewall
hole to allow the backup.
3. On the server when the dump completes DumpPostUserCmd runs and
removes the hostname.html file.
4. When the periodic task on the windows machine no longer finds the
hostname.html file it stops the rsyncd service, deletes the shadow
copies, and closes the firewall hole.
It works fine unless the backup get's interupted while DumpPreUserCmd is
running and waiting for windows to start it's rsyncd service. In that
case the hostname.html file get's orphaned.
I *could* create a cron job on the server to look for and remove
orphaned hostname.html files, but I'm hoping to not need that.
Thanks
Russ Poyner
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[BackupPC-users] V4 for production?
I'm in the process of building a BackupPC set up for about 200 users. The possibility of incrementals forever that looks to be available in V4 is quite appealing. My experience backing up windows PC's with V3 has been that the fulls take a long time and are much more likely to fail than incrementals. I've been using a script run via cygwin/ssh on the windows machines that creates a shadow copy and makes it available to BackupPC via rsyncd. Not having to run regular, trouble-prone fulls of windows clients would be great. So am I insane to be thinking about V4 on a sizeable production system? R Poyner -- WatchGuard Dimension instantly turns raw network data into actionable security intelligence. It gives you real-time visual feedback on key security issues and trends. Skip the complicated setup - simply import a virtual appliance and go from zero to informed in seconds. http://pubads.g.doubleclick.net/gampad/clk?id=123612991iu=/4140/ostg.clktrk ___ 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] What file system do you use?
Mark, Questions, and some comments. Questions: What have you done to tune your zfs? Do you use a ZIL? and or an L2ARC? How much ram do you have? What compression level are you using on zfs? I reflexively put a ZIL on my system but I'm curious if anyone has experimented with BackupPC performance on zfs with and without the ZIL. Comments: I built a backuppc on zfs system at my last job, but I took the opposite approach on compression. I disabled compression and dedupe on zfs and let BackupPC handle those jobs. I haven't seen load problems, but I do notice that the tranfer speed reported by backuppc varies a lot between different windows clients. Anywhere from 1.4 MB/s to 41 MB/s. This is partly due to network speed since some machines are on Gb connections, but most are on 100Mb. There also seems to be some dependence on the age and condition of the windows boxes. BackupPC reports 76486 Gb of fulls and 1442 Gb of incrementals. zfs list shows 11.9 Tb allocated from the 65Tb pool for backuppc data. Which gives me about a 6.4 fold reduction in storage, slightly less than the roughly 7.5 fold reduction that you see. My data comes from user files on 12 windows 7 machines. This is a poor comparison since we have different data sets, but it would appear that BackupPC's internal dedupe and compression is comparable to, or only slightly worse than what zfs achieves. This in spite of the expectation that zfs block level dedupe might find more duplication than BackupPC's file level dedupe. Russ Poyner On 12/17/13 07:50, Mark Campbell wrote:20 I too am using ZFS, and I can honestly say that ZFS works great, up to a point. rsync does seem to take up an inordinate amount of resources, but in a smaller shop like mine, it's been tolerable. I think it would work in a larger shop too, but the system resource requirements (CPU/RAM) would grow larger than what you would expect normally. I've had a couple of instances of performance issues in my setup, where over time, rsync was uploading data to the system faster than zfs could process it, and so I'd watch my load go through the roof (8.00+ on a quad core system), and I would have to stop BackupPC for an hour or so, so that ZFS could catch up, but other than that, this system has actually handled it fairly well. What I really like about ZFS though, is the deduplication coupled with compression. I've disabled compression in BackupPC to allow ZFS to properly do the dedup compression (enabling compression in BackupPC kills ZFS' dedup ability, since it messes with the checksums of the files), and I'm getting numbers in the range of 4.xx deduplication. My ZFS array is 1.12TB in size, yet, according to BackupPC, I've got 1800GB in fulls, and 2400GB in incrementals. When I query the array for actual disk usage, it says I'm using 557GB of space... Now that's just too cool. Thanks, --Mark -Original Message- From: Tim Connors [mailto:tconn...@rather.puzzling.org] Sent: Monday, December 16, 2013 10:00 PM To: General list for user discussion, questions and support Subject: Re: [BackupPC-users] What file system do you use? On Mon, 16 Dec 2013, Timothy J Massey wrote: One last thing: everyone who uses ZFS raves about it. But seeing as (on Linux) you're limited to either FUSE or out-of-tree kernel modules (of questionable legality: ZFS' CDDL license is *not* GPL compatible), it's not my first choice for a backup server, either. I am using it, and it sucks for a backuppc load (in fact, from the mailing list, it is currently (and has been for a couple of years) terrible on an rsync style workload - any metadata heavy workload will eventually crash the machine after a couple of weeks uptime. Some patches are being tested right now out of tree that look promising, but I won't be testing them myself until it hits master 0.6.3. Problem for me is that it takes about a month to migrate to a new filesystem. I migrated to zfs a couple of years ago with insufficient testing. I should have kept on ext4+mdadm (XFS was terrible too - no faster than ext4, and given that I've always lost data on various systems with it because it's such a flaky filesystem, I wasn't gaining anything). mdadm is more flexible than ZFS, although harder to configure. With mdadm+ext4, you can choose any disk arrangement you like without being limited to simple RAID-Z(n) arrangements of equal sized disks. That said, I do prefer ZFS's scrubbing compared to mdadm's, but only slightly. If I was starting from scratch and didn't have 4-5 years of backup archives, I'd tell backuppc to turn off compression and munging of the pool, and let ZFS do it. I used JFS 10 years ago, and niche buggy product would be my description for it. Basically, go with the well tested popular FSs, because they're not as bad as everyone makes them out to be. -- Tim Connors
Re: [BackupPC-users] What file system do you use?
Thanks Mark. From the zfs man page for zol it looks like the default compression is lzjb, same as other zfs implementations. I generally use lz4 which is basically lzjb with some performance upgrades. It's a minor tweak unless you have a lot of uncompressible files. If you are experiencing decent data rates without a separate ZIL, it likely means that BackupPC is not doing synchronous writes. Answers one of my longstanding questions about BPC. It's possible that your performance stalls are related to the size of your dedupe table. Performance will tank if you are having to read the dedupe table from disk, rather than have all of it cached in ram. This is a well known performance issue with zfs dedupe. There is a good discussion of the issue here: http://constantin.glez.de/blog/2011/07/zfs-dedupe-or-not-dedupe I suspect that using an ssd as l2arc to hold the extra dedupe would give adequate performance for backups. RP On 12/17/13 11:52, Mark Campbell wrote: I've done virtually no tuning of ZFS. In my initial experimentations with ZFS, I was blowing away my array so often when trying different combinations of BPC commpress/ZFS compress/ZFS dedup that I wrote a little shell script that recreated the ZFS array populated the necessary directories for BackupPC: #!/bin/bash bpcdir=/backup/BackupPC service backuppc stop zpool destroy -f backup zpool create backup raidz2 sdc sdd sde sdf sdg sdh zfs set compression=on backup zfs set dedup=on backup zfs set atime=off backup mkdir $bpcdir chown backuppc $bpcdir chmod 750 $bpcdir cd $bpcdir mkdir cpool pc pool chown backuppc * chmod 750 * service backuppc start That's pretty much the extent of my tuning of ZFS. This is a CentOS 6.4 x86_64 system, with ZoL installed. I've got 6 250GB disks installed on a 3ware SATA RAID card set to be stand alone disks, 16GB of RAM, which has served me well, no swapping, so that's been good. I've tried to avoid intermediary caches for sake of performance. For the level of compression, just whatever is default (isn't it normally 6?). In my case, my data comes from 16 hosts, a mix of linux, winxp, win7, win8 machines. My biggest backup client is a network drive, CentOS 6 based, that is housing all sorts of files, but is also a repository of backups in and of itself for some Server 2012 backups. This is a variety of stuff, ranging from SQL Server backups, to full bare metal system backups, which most unfortunately, presents itself as a few gigantic files. Some of these backups are dozens, if not hundreds of GB in size. And all that was changing in these files were a few MB worth from day to day, so I can totally empathize with Timothy's gripes with Exchange. File-based deduplication wasn't helping me here, so that's why I tried out ZFS. And boy, does it work. I'm really only doing about 10 backups at a time right now; The same basic system (- ZFS, + BackupCP compression) was reaching 95% capacity with just 3 backups before. I guarantee that were I storing more backups, my 7.5 fold reduction would skyroc ket even higher. Thanks, --Mark -Original Message- From: Russell R Poyner [mailto:rpoy...@engr.wisc.edu] Sent: Tuesday, December 17, 2013 11:12 AM To: backuppc-users@lists.sourceforge.net Cc: Mark Campbell Subject: Re: [BackupPC-users] What file system do you use? Mark, Questions, and some comments. Questions: What have you done to tune your zfs? Do you use a ZIL? and or an L2ARC? How much ram do you have? What compression level are you using on zfs? I reflexively put a ZIL on my system but I'm curious if anyone has experimented with BackupPC performance on zfs with and without the ZIL. Comments: I built a backuppc on zfs system at my last job, but I took the opposite approach on compression. I disabled compression and dedupe on zfs and let BackupPC handle those jobs. I haven't seen load problems, but I do notice that the tranfer speed reported by backuppc varies a lot between different windows clients. Anywhere from 1.4 MB/s to 41 MB/s. This is partly due to network speed since some machines are on Gb connections, but most are on 100Mb. There also seems to be some dependence on the age and condition of the windows boxes. BackupPC reports 76486 Gb of fulls and 1442 Gb of incrementals. zfs list shows 11.9 Tb allocated from the 65Tb pool for backuppc data. Which gives me about a 6.4 fold reduction in storage, slightly less than the roughly 7.5 fold reduction that you see. My data comes from user files on 12 windows 7 machines. This is a poor comparison since we have different data sets, but it would appear that BackupPC's internal dedupe and compression is comparable to, or only slightly worse than what zfs achieves. This in spite of the expectation that zfs block level dedupe might find more duplication than BackupPC's file level dedupe. Russ Poyner On 12/17/13 07:50
[BackupPC-users] BackupPC for laptops?
At my last job I built a BackupPC setup that worked well for windows desktops using vss and rsyncd. In my new position I'm looking for options for backing up laptops and tablets. Most of these machines rarely connect to our wired network or vpn. Which means they are normally separated by our firewall from the backupPC server. I'm hoping to find a solution that can backup the laptops over whatever wireless network they happen to be on. Solutions like CrashPlan, Carbonite or BackBlaze offer continuous backup over nearly any internet connection. Our users don't want a 3rd party storing their data so I'm wondering if this sort of thing is possible with BackupPC. Russ Poyner -- Sponsored by Intel(R) XDK Develop, test and display web and hybrid apps with a single code base. Download it for free now! http://pubads.g.doubleclick.net/gampad/clk?id=111408631iu=/4140/ostg.clktrk ___ 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/
