Re: split RAID1 during backups?

2005-10-29 Thread Jeff Breidenbach
Thanks to good advice from many people, here are my findings and conclusions. (1) Splitting the RAID works. I have now implemented this technique on the production system and am making a backup right now. (2) NBD is cool, works well on Debian, and is very convenient. A couple experiments

Re: split RAID1 during backups?

2005-10-27 Thread Bill Davidsen
On Wed, 26 Oct 2005, Jeff Breidenbach wrote: Norman What you should be able to do with software raid1 is the Norman following: Stop the raid, mount both underlying devices Norman instead of the raid device, but of course READ ONLY. Both Norman contain the complete data and filesystem, and

split RAID1 during backups?

2005-10-26 Thread Jeff Breidenbach
Norman What you should be able to do with software raid1 is the Norman following: Stop the raid, mount both underlying devices Norman instead of the raid device, but of course READ ONLY. Both Norman contain the complete data and filesystem, and in addition to Norman that the md superblock at the

Re: split RAID1 during backups?

2005-10-26 Thread Christopher Smith
Jeff Breidenbach wrote: Hi all, [...] So - I'm thinking of the following backup scenario. First, remount /dev/md0 readonly just to be safe. Then mount the two component paritions (sdc1, sdd1) readonly. Tell the webserver to work from one component partition, and tell the backup process to

Re: split RAID1 during backups?

2005-10-25 Thread Norman Schmidt
Jeff Breidenbach schrieb: Ok... thanks everyone! Something from me: What you should be able to do with software raid1 is the following: Stop the raid, mount both underlying devices instead of the raid device, but of course READ ONLY. Both contain the complete data and filesystem, and in

Re: split RAID1 during backups?

2005-10-25 Thread John Stoffel
Norman What you should be able to do with software raid1 is the Norman following: Stop the raid, mount both underlying devices Norman instead of the raid device, but of course READ ONLY. Both Norman contain the complete data and filesystem, and in addition to Norman that the md superblock at the

Re: split RAID1 during backups?

2005-10-25 Thread Paul Clements
Jeff Breidenbach wrote: your suggestion about kernel 2.6.13 and intent logging and having mdadm pull a disk sounds like a winner. I'm going to to try it if the software looks mature enough. Should I be scared? There have been a couple bug fixes in the bitmap stuff since 2.6.13 was released,

Re: split RAID1 during backups?

2005-10-25 Thread Norman Schmidt
John Stoffel schrieb: Norman What you should be able to do with software raid1 is the Norman following: Stop the raid, mount both underlying devices Norman instead of the raid device, but of course READ ONLY. Both Norman contain the complete data and filesystem, and in addition to Norman that

Re: split RAID1 during backups?

2005-10-25 Thread Bill Davidsen
On Mon, 24 Oct 2005, Jeff Breidenbach wrote: Ok... thanks everyone! David, you said you are worried about failure scenarios involved with RAID splitting. Could you please elaborate? My biggest concern is I'm going to accidentally trigger a rebuild no matter what I try but maybe you have

Re[2]: split RAID1 during backups?

2005-10-25 Thread Rainer Fuegenstein
Hi, don't know if my comment helps: how about using xfs instead of reiserfs ? xfs was designed for high performance on heavy-loaded big irons. since we now have such a heavy-loaded big iron here, it would be interesting to see the difference in performance. -- Best regards, Rainer

Re: split RAID1 during backups?

2005-10-25 Thread David Greaves
Jeff Breidenbach wrote: Individual directories contain up to about 150,000 files. If I run ls -U on all directories, it completes in a reasonably amount of time (I forget how much, but I think it is well under an hour). Reiserfs is supposed to be good at this sort of thing. If I were to stat each

split RAID1 during backups?

2005-10-24 Thread Jeff Breidenbach
Hi all, I have a two drive RAID1 serving data for a busy website. The partition is 500GB and contains millions of 10KB files. For reference, here's /proc/mdstat Personalities : [raid1] md0 : active raid1 sdc1[0] sdd1[1] 488383936 blocks [2/2] [UU] For backups, I set the md0 partition to

Re: split RAID1 during backups?

2005-10-24 Thread Jurriaan Kalkman
Hi all, I have a two drive RAID1 serving data for a busy website. The partition is 500GB and contains millions of 10KB files. For reference, here's /proc/mdstat Personalities : [raid1] md0 : active raid1 sdc1[0] sdd1[1] 488383936 blocks [2/2] [UU] For backups, I set the md0

Re: split RAID1 during backups?

2005-10-24 Thread Brad Campbell
Jeff Breidenbach wrote: So - I'm thinking of the following backup scenario. First, remount /dev/md0 readonly just to be safe. Then mount the two component paritions (sdc1, sdd1) readonly. Tell the webserver to work from one component partition, and tell the backup process to work from the

Re: split RAID1 during backups?

2005-10-24 Thread Jeff Breidenbach
First of all, if the data is mostly static, rsync might work faster. Any operation that stats the individual files - even to just look at timestamps - takes about two weeks. Therefore it is hard for me to see rsync as a viable solution, even though the data is mostly static. About 400,000 files

Re: split RAID1 during backups?

2005-10-24 Thread dean gaudet
On Mon, 24 Oct 2005, Jeff Breidenbach wrote: First of all, if the data is mostly static, rsync might work faster. Any operation that stats the individual files - even to just look at timestamps - takes about two weeks. Therefore it is hard for me to see rsync as a viable solution, even

Re: split RAID1 during backups?

2005-10-24 Thread John Stoffel
Jeff == Jeff Breidenbach jeff@jab.org writes: Jeff # mount | grep md0 Jeff /dev/md0 on /data1 type reiserfs (rw,noatime,nodiratime) Ah, you're using reiserfs on here. It may or may not be having problems with all those files per-directory that you have. Is there any way you can split them up

Re: split RAID1 during backups?

2005-10-24 Thread dean gaudet
On Mon, 24 Oct 2005, Jeff Breidenbach wrote: Dean, the comment about write-mostly is confusing to me. Let's say I somehow marked one of the component drives write-mostly to quiet it down. How do I get at it? Linux will not let me mount the component partition if md0 is also mounted. Do you

Re: split RAID1 during backups?

2005-10-24 Thread Thomas Garner
Should there be any consideration for the utilization of the gigabit interface that is passing all of this backup traffic, as well as the speed of the drive that is doing all of the writing during this transaction? Is the 18MB/s how fast the data is being copied over the network, or is it

Re: split RAID1 during backups?

2005-10-24 Thread Jeff Breidenbach
On 10/24/05, Thomas Garner [EMAIL PROTECTED] wrote: Should there be any consideration for the utilization of the gigabit interface that is passing all of this backup traffic, as well as the speed of the drive that is doing all of the writing during this transaction? Is the 18MB/s how fast