xfs_freeze is a userspace program included in the xfsprogs rpm. It does run on Redhat 7.3 (the SGI supplied kernels and userspace for RedHat 7.3 are somewhat dated; I'd suggest patching the 2.4.21 kernel with XFS 1.3.1 patches and upgrading the userspace programs from the SRPMS). Post to the linux-xfs mailing list if you need further guidance (lots of people seem to still run XFS on Redhat 7.3).
> -----Original Message----- > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] > Sent: Thursday, October 30, 2003 12:28 PM > To: [EMAIL PROTECTED]; [EMAIL PROTECTED] > Cc: [EMAIL PROTECTED]; [EMAIL PROTECTED]; [EMAIL PROTECTED]; > [EMAIL PROTECTED]; [EMAIL PROTECTED] > Subject: Re: [linux-lvm] RE: [ADMIN] [PERFORM] backup/restore > - another > > > Does xfs_freeze work on red hat 7.3? > > Cynthia Leon > > -----Original Message----- > From: Murthy Kambhampaty [mailto:[EMAIL PROTECTED] > Sent: Friday, October 17, 2003 11:34 AM > To: 'Tom Lane'; Murthy Kambhampaty > Cc: 'Jeff'; Josh Berkus; [EMAIL PROTECTED]; > [EMAIL PROTECTED]; [EMAIL PROTECTED]; > [EMAIL PROTECTED] > Subject: [linux-lvm] RE: [ADMIN] [PERFORM] backup/restore - another > area. > > > Friday, October 17, 2003 12:05, Tom Lane > [mailto:[EMAIL PROTECTED] wrote: > > >Murthy Kambhampaty <[EMAIL PROTECTED]> writes: > >> ... The script handles situations > >> where (i) the XFS filesystem containing $PGDATA has an > >external log and (ii) > >> the postmaster log ($PGDATA/pg_xlog) is written to a > >filesystem different > >> than the one containing the $PGDATA folder. > > > >It does? How exactly can you ensure snapshot consistency between > >data files and XLOG if they are on different filesystem > > Say, you're setup looks something like this: > > mount -t xfs /dev/VG1/LV_data /home/pgdata > mount -t xfs /dev/VG1/LV_xlog /home/pgdata/pg_xlog > > When you want to take the filesystem backup, you do: > > Step 1: > xfs_freeze -f /dev/VG1/LV_xlog > xfs_freeze -f /dev/VG1/LV_data > This should finish any checkpoints that were in > progress, and not > start any new ones > till you unfreeze. (writes to an xfs_frozen filesystem > wait for the > xfs_freeze -u, > but reads proceed; see text from xfs_freeze manpage in postcript > below.) > > > Step2: > create snapshots of /dev/VG1/LV_xlog and /dev/VG1/LV_xlog > > Step 3: > xfs_freeze -u /dev/VG1/LV_data > xfs_freeze -u /dev/VG1/LV_xlog > Unfreezing in this order should assure that checkpoints > resume where > they left off, then log writes commence. > > > Step4: > mount the snapshots taken in Step2 somewhere; e.g. /mnt/snap_data and > /mnt/snap_xlog. Copy (or rsync or whatever) /mnt/snap_data to > /mnt/pgbackup/ > and /mnt/snap_xlog to /mnt/pgbackup/pg_xlog. Upon completion, > /mnt/pgbackup/ > looks to the postmaster like /home/pgdata would if the server > had crashed at > the moment that Step1 was initiated. As I understand it, > during recovery > (startup) the postmaster will roll the database forward to this point, > "checkpoint-ing" all the transactions that made it into the > log before the > crash. > > Step5: > remove the snapshots created in Step2. > > The key is > (i) xfs_freeze allows you to "quiesce" any filesystem at any > point in time > and, if I'm not mistaken, the order (LIFO) in which you > freeze and unfreeze > the two filesystems: freeze $PGDATA/pg_xlog then $PGDATA; > unfreeze $PGDATA > then $PGDATA/pg_xlog. > (ii) WAL recovery assures consistency after a (file)sytem crash. > > Presently, the test server for my backup scripts is set-up > this way, and the > backup works flawlessly, AFAICT. (Note that the backup script starts a > postmaster on the filesystem copy each time, so you get early > warning of > problems. Moreover the data in the "production" and "backup" > copies are > tested and found to be identical. > > Comments? Any suggestions for additional tests? > > Thanks, > Murthy > > PS: From the xfs_freeze manpage: > "xfs_freeze suspends and resumes access to an XFS filesystem (see > xfs(5)). > > xfs_freeze halts new access to the filesystem and creates a > stable image > on disk. xfs_freeze is intended to be used with volume managers and > hardware RAID devices that support the creation of snapshots. > > The mount-point argument is the pathname of the directory where the > filesystem is mounted. The filesystem must be mounted to be > frozen (see > mount(8)). > > The -f flag requests the specified XFS filesystem to be > frozen from new > modifications. When this is selected, all ongoing transactions in the > filesystem are allowed to complete, new write system calls are halted, > other calls which modify the filesystem are halted, and all > dirty data, > metadata, and log information are written to disk. Any process > attempting to write to the frozen filesystem will block > waiting for the > filesystem to be unfrozen. > > Note that even after freezing, the on-disk filesystem can contain > information on files that are still in the process of unlinking. These > files will not be unlinked until the filesystem is unfrozen or a clean > mount of the snapshot is complete. > > The -u option is used to un-freeze the filesystem and allow operations > to continue. Any filesystem modifications that were blocked by the > freeze are unblocked and allowed to complete." > > _______________________________________________ > linux-lvm mailing list > [EMAIL PROTECTED] > http://lists.sistina.com/mailman/listinfo/linux-lvm > read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/ > > ============================================================== > ================ > --- PRESBYTERIAN HEALTHCARE SERVICES DISCLAIMER --- > > This message originates from Presbyterian Healthcare Services > or one of its > affiliated organizations. It contains information, which may > be confidential > or privileged, and is intended only for the individual or > entity named above. > It is prohibited for anyone else to disclose, copy, > distribute or use the > contents of this message. 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