Re: Copying mirrored partitions - will this work?
On Wednesday 31 March 2010, krad wrote: > On 31 March 2010 10:22, Mike Clarke wrote: > > On Saturday 20 March 2010, Mike Clarke wrote: [snip] > > > I have two 500GB disks, /dev/ad4 and /dev/ad8, each partitioned > > > into 4 slices of 88, 88, 42 and 259GB. My system is installed on > > > the first slices (ad4s1 and ad8s1) which are mirrored as > > > /dev/mirror/gm0. The second slices (ad4s2 and ad8s2) are > > > currently unused. My thoughts are to temporarily add ad4s2 into > > > gm0 with "gmirror insert gm0 ad4s2" and wait for the mirror to > > > synchronise. I should then be able to remove the temporary > > > addition with "gmirror remove gm0 /dev/ad4s2" at which point > > > ad4s2 should be a duplicate of the original system and I can then > > > go ahead and create a new mirror with "gmirror label -b load gm1 > > > ad4s2" and "gmirror insert gm1 ad8s2". After editing /etc/fstab > > > in the new mirror to use gm1 instead of gm0 I should then be able > > > to boot into the system on slice 2 and upgrade it to STABLE while > > > still keeping my original system to fall back to if required. > > > > > > Is this approach of moving disks from one mirror to another > > > workable, or have I missed something that would lead me into deep > > > trouble? I don't mind unduly if I make a mess of the second slice > > > and have to start again but I don't want to lose the contents of > > > my original system on slice 1. > > > > I decided to give it a try and the process went through very > > smoothly. It was much less tedious than bsdlabel -> newfs -> > > dump|restore, and quicker too. The mirror synchronised at a bit > > over 100 MB/sec but dump| restore only gave me about 10 MB/sec. [snip] > One thing about your dump/restore speed. Did you play around with > larger block sizes? Increasing it should give you better throughput. I used 32 MB for the cache size but I expect the reduced speed comes about from the need to find and open a large number of files whereas synchronising the mirror just does a sequential disk to disk copy at block level. -- Mike Clarke ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "freebsd-questions-unsubscr...@freebsd.org"
Re: Copying mirrored partitions - will this work?
On 31 March 2010 10:22, Mike Clarke wrote: > On Saturday 20 March 2010, Mike Clarke wrote: > > > I'm currently running 8.0-RELEASE and am considering experimenting > > with 8.0-STABLE. I'd like to preserve my existing system in case > > things go pear-shaped so I'll copy the entire system onto a spare > > slice and then use csup to upgrade the copy to STABLE. Normally I'd > > go through the steps of bsdlabel, newfs and then dump|restore to > > create the copy but I'm wondering if I can take advantage of my > > recently created gmirror to cut down the work. > > > > I have two 500GB disks, /dev/ad4 and /dev/ad8, each partitioned into > > 4 slices of 88, 88, 42 and 259GB. My system is installed on the first > > slices (ad4s1 and ad8s1) which are mirrored as /dev/mirror/gm0. The > > second slices (ad4s2 and ad8s2) are currently unused. My thoughts are > > to temporarily add ad4s2 into gm0 with "gmirror insert gm0 ad4s2" and > > wait for the mirror to synchronise. I should then be able to remove > > the temporary addition with "gmirror remove gm0 /dev/ad4s2" at which > > point ad4s2 should be a duplicate of the original system and I can > > then go ahead and create a new mirror with "gmirror label -b load gm1 > > ad4s2" and "gmirror insert gm1 ad8s2". After editing /etc/fstab in > > the new mirror to use gm1 instead of gm0 I should then be able to > > boot into the system on slice 2 and upgrade it to STABLE while still > > keeping my original system to fall back to if required. > > > > Is this approach of moving disks from one mirror to another workable, > > or have I missed something that would lead me into deep trouble? I > > don't mind unduly if I make a mess of the second slice and have to > > start again but I don't want to lose the contents of my original > > system on slice 1. > > I decided to give it a try and the process went through very smoothly. > It was much less tedious than bsdlabel -> newfs -> dump|restore, and > quicker too. The mirror synchronised at a bit over 100 MB/sec but dump| > restore only gave me about 10 MB/sec. > > The system has now been running for a bit over a week without any > problems with either the original or cloned slices so I'm quite > confident that things are OK. > > -- > Mike Clarke > ___ > freebsd-questions@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-questions > To unsubscribe, send any mail to " > freebsd-questions-unsubscr...@freebsd.org" > ive cloned many systems in this way before, and it does work. Not just gmirror two, it should work with any mirroring, hardware or software. One thing to remember though is that it works at the block level. Therefore if the drive if very big with a small % of data on it might be quicker to copy it manually. There is always an exception though. If you are using zfs, then only the data on the drive is copied. This is because zfs works at block, and file system levels, and therefore is aware of what is allocated on the disks. One thing about your dump/restore speed. Did you play around with larger block sizes? Increasing it should give you better throughput. ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "freebsd-questions-unsubscr...@freebsd.org"
Re: Copying mirrored partitions - will this work?
On Saturday 20 March 2010, Mike Clarke wrote: > I'm currently running 8.0-RELEASE and am considering experimenting > with 8.0-STABLE. I'd like to preserve my existing system in case > things go pear-shaped so I'll copy the entire system onto a spare > slice and then use csup to upgrade the copy to STABLE. Normally I'd > go through the steps of bsdlabel, newfs and then dump|restore to > create the copy but I'm wondering if I can take advantage of my > recently created gmirror to cut down the work. > > I have two 500GB disks, /dev/ad4 and /dev/ad8, each partitioned into > 4 slices of 88, 88, 42 and 259GB. My system is installed on the first > slices (ad4s1 and ad8s1) which are mirrored as /dev/mirror/gm0. The > second slices (ad4s2 and ad8s2) are currently unused. My thoughts are > to temporarily add ad4s2 into gm0 with "gmirror insert gm0 ad4s2" and > wait for the mirror to synchronise. I should then be able to remove > the temporary addition with "gmirror remove gm0 /dev/ad4s2" at which > point ad4s2 should be a duplicate of the original system and I can > then go ahead and create a new mirror with "gmirror label -b load gm1 > ad4s2" and "gmirror insert gm1 ad8s2". After editing /etc/fstab in > the new mirror to use gm1 instead of gm0 I should then be able to > boot into the system on slice 2 and upgrade it to STABLE while still > keeping my original system to fall back to if required. > > Is this approach of moving disks from one mirror to another workable, > or have I missed something that would lead me into deep trouble? I > don't mind unduly if I make a mess of the second slice and have to > start again but I don't want to lose the contents of my original > system on slice 1. I decided to give it a try and the process went through very smoothly. It was much less tedious than bsdlabel -> newfs -> dump|restore, and quicker too. The mirror synchronised at a bit over 100 MB/sec but dump| restore only gave me about 10 MB/sec. The system has now been running for a bit over a week without any problems with either the original or cloned slices so I'm quite confident that things are OK. -- Mike Clarke ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "freebsd-questions-unsubscr...@freebsd.org"
Re: Copying mirrored partitions - will this work?
On Sunday 21 March 2010, Modulok wrote: > On 3/20/10, Mike Clarke wrote: [snip] > > I have two 500GB disks, /dev/ad4 and /dev/ad8, each partitioned > > into 4 slices of 88, 88, 42 and 259GB. My system is installed on > > the first slices (ad4s1 and ad8s1) which are mirrored as > > /dev/mirror/gm0. The second slices (ad4s2 and ad8s2) are currently > > unused. My thoughts are to temporarily add ad4s2 into gm0 with > > "gmirror insert gm0 ad4s2" and wait for the mirror to synchronise. > > I should then be able to remove the temporary addition with > > "gmirror remove gm0 /dev/ad4s2" at which point ad4s2 should be a > > duplicate of the original system and I can then go ahead and create > > a new mirror with "gmirror label -b load gm1 ad4s2" and "gmirror > > insert gm1 ad8s2". After editing /etc/fstab in the new mirror to > > use gm1 instead of gm0 I should then be able to boot into the > > system on slice 2 and upgrade it to STABLE while still keeping my > > original system to fall back to if required. > How valuable is your data? In financial terms not very, but still valuable enough to not want to lose it. > I recommend you make an offline backup. Yes, I take regular backups but regard them as the "emergency parachute" and prefer to not put myself in a position where I'm doing something risky and the backup files are the only protection, so I'll be making additional backups anyway. > There's a lot of steps in > your procedure which introduce room for error. Yes, it's a bit of unknown territory for me but with 6 partitions on the slice it does require fewer potentially dangerous manual steps (like newfs or restore to the wrong device) so looks like an interesting experiment. > You could perhaps > disconnect one of the hard drive's data cable (same thing). Also, > make a backup copy of your geom meta data somewhere. That's a possibility to consider but would result in additional changes to the mirror configuration, something I'd prefer to keep to a minimum. -- Mike Clarke ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "freebsd-questions-unsubscr...@freebsd.org"
Re: Copying mirrored partitions - will this work?
How valuable is your data? I recommend you make an offline backup. There's a lot of steps in your procedure which introduce room for error. You could perhaps disconnect one of the hard drive's data cable (same thing). Also, make a backup copy of your geom meta data somewhere. Other than that, your procedure sounds like it should work. Though, I've never tried it. I do recall, that when updating from 6.2-RELEASE to 8-RELEASE, the geom meta data was automatically updated. I'm not sure if there is any change between Release and Stable, though. I'm also not sure if it was a backward incompatible change, as I never went back to 6.2. Just something to be aware of. Sorry I can't be more helpful. Maybe someone else knows more. -Modulok- On 3/20/10, Mike Clarke wrote: > > I'm currently running 8.0-RELEASE and am considering experimenting with > 8.0-STABLE. I'd like to preserve my existing system in case things go > pear-shaped so I'll copy the entire system onto a spare slice and then > use csup to upgrade the copy to STABLE. Normally I'd go through the > steps of bsdlabel, newfs and then dump|restore to create the copy but > I'm wondering if I can take advantage of my recently created gmirror to > cut down the work. > > I have two 500GB disks, /dev/ad4 and /dev/ad8, each partitioned into 4 > slices of 88, 88, 42 and 259GB. My system is installed on the first > slices (ad4s1 and ad8s1) which are mirrored as /dev/mirror/gm0. The > second slices (ad4s2 and ad8s2) are currently unused. My thoughts are > to temporarily add ad4s2 into gm0 with "gmirror insert gm0 ad4s2" and > wait for the mirror to synchronise. I should then be able to remove the > temporary addition with "gmirror remove gm0 /dev/ad4s2" at which point > ad4s2 should be a duplicate of the original system and I can then go > ahead and create a new mirror with "gmirror label -b load gm1 ad4s2" > and "gmirror insert gm1 ad8s2". After editing /etc/fstab in the new > mirror to use gm1 instead of gm0 I should then be able to boot into the > system on slice 2 and upgrade it to STABLE while still keeping my > original system to fall back to if required. > > Is this approach of moving disks from one mirror to another workable, or > have I missed something that would lead me into deep trouble? I don't > mind unduly if I make a mess of the second slice and have to start > again but I don't want to lose the contents of my original system on > slice 1. > > -- > Mike Clarke > ___ > freebsd-questions@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-questions > To unsubscribe, send any mail to "freebsd-questions-unsubscr...@freebsd.org" > ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "freebsd-questions-unsubscr...@freebsd.org"
Copying mirrored partitions - will this work?
I'm currently running 8.0-RELEASE and am considering experimenting with 8.0-STABLE. I'd like to preserve my existing system in case things go pear-shaped so I'll copy the entire system onto a spare slice and then use csup to upgrade the copy to STABLE. Normally I'd go through the steps of bsdlabel, newfs and then dump|restore to create the copy but I'm wondering if I can take advantage of my recently created gmirror to cut down the work. I have two 500GB disks, /dev/ad4 and /dev/ad8, each partitioned into 4 slices of 88, 88, 42 and 259GB. My system is installed on the first slices (ad4s1 and ad8s1) which are mirrored as /dev/mirror/gm0. The second slices (ad4s2 and ad8s2) are currently unused. My thoughts are to temporarily add ad4s2 into gm0 with "gmirror insert gm0 ad4s2" and wait for the mirror to synchronise. I should then be able to remove the temporary addition with "gmirror remove gm0 /dev/ad4s2" at which point ad4s2 should be a duplicate of the original system and I can then go ahead and create a new mirror with "gmirror label -b load gm1 ad4s2" and "gmirror insert gm1 ad8s2". After editing /etc/fstab in the new mirror to use gm1 instead of gm0 I should then be able to boot into the system on slice 2 and upgrade it to STABLE while still keeping my original system to fall back to if required. Is this approach of moving disks from one mirror to another workable, or have I missed something that would lead me into deep trouble? I don't mind unduly if I make a mess of the second slice and have to start again but I don't want to lose the contents of my original system on slice 1. -- Mike Clarke ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "freebsd-questions-unsubscr...@freebsd.org"
