zfs snapshots for TAPE backup: 1: must be of entire pool? 2:if yes, then need TWICE as much disk?
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From: Richard B. Gilbert on 16 Feb 2010 17:21 nelson wrote: >> When you make a snapsnot that you want to put onto a tape for off-site >> backup, is it the entire pool you have to snapshot? > it can be, but doesn't have to be. it's at the filesystem/volume > level > >> Now, a snapshot that is to go to tape will of course contain EVERYTHING >> descending from that point (entire pool?). > depends on whether you're using volumes within a pool > >> And before tarring it off, doesn't it have to first be on disk, and then >> you write it from there? > not sure i follow, it's early and i need coffee but you can access the > snapshot > under the ZFS-volume-path/.zfs/snapshot/$SNAPSHOTNAME. you could > also clone it and mount it somewhere else or ZFS send it. > >> Like maybe you want to bzip2 the thing first? (So it fits on the tape.) > could certainly pipe a send through some form of compression or have > the tape > handle it The FIRST thing you want to think about is "HOW AM I GOING TO RESTORE THIS?". If your system disk failed, you are going to have to repair or replace the disk, boot from CD/DVD and then do your restore. There is much to be said for taking your backup to a test system, booting that system from CD/DVD and actually restoring your file systems! If you do this, you will KNOW that you CAN do this. Or if things do not go well, you KNOW that you CAN'T restore successfully and that you will need to take corrective action. You DO NOT want to become the guy who could not restore his employer's accounts receivable! That could mean that your only recourse is to attend "Hamburger University" and get a job managing a McDonald's! And it's not JUST accounts receivable. Files of many sorts can and probably will contain business critical information. Consider whether the extra time to "unbzip" before you can restore is going to be critical. Is bzip on the install CD/DVD? If not, where is it and how are you going to install it? Can bzip run standalone or must the O/S be installed in order for bzip to work? Whether a backup fits on one tape or two is one of the LAST things to worry about!
From: David Combs on 17 Mar 2010 00:15 In article <TdWdnXxxPpTvh-bWnZ2dnUVZ_vSdnZ2d(a)giganews.com>, Richard B. Gilbert <rgilbert88(a)comcast.net> wrote: >nelson wrote: >>> When you make a snapsnot that you want to put onto a tape for off-site >>> backup, is it the entire pool you have to snapshot? >> it can be, but doesn't have to be. it's at the filesystem/volume >> level >> >>> Now, a snapshot that is to go to tape will of course contain EVERYTHING >>> descending from that point (entire pool?). >> depends on whether you're using volumes within a pool >> >>> And before tarring it off, doesn't it have to first be on disk, and then >>> you write it from there? >> not sure i follow, it's early and i need coffee but you can access the >> snapshot >> under the ZFS-volume-path/.zfs/snapshot/$SNAPSHOTNAME. you could >> also clone it and mount it somewhere else or ZFS send it. >> >>> Like maybe you want to bzip2 the thing first? (So it fits on the tape.) >> could certainly pipe a send through some form of compression or have >> the tape >> handle it > >The FIRST thing you want to think about is "HOW AM I GOING TO RESTORE >THIS?". If your system disk failed, you are going to have to repair or >replace the disk, boot from CD/DVD and then do your restore. > >There is much to be said for taking your backup to a test system, >booting that system from CD/DVD and actually restoring your file >systems! If you do this, you will KNOW that you CAN do this. Or if >things do not go well, you KNOW that you CAN'T restore successfully and >that you will need to take corrective action. > >You DO NOT want to become the guy who could not restore his employer's >accounts receivable! That could mean that your only recourse is to >attend "Hamburger University" and get a job managing a McDonald's! > >And it's not JUST accounts receivable. Files of many sorts can and >probably will contain business critical information. > >Consider whether the extra time to "unbzip" before you can restore is >going to be critical. Is bzip on the install CD/DVD? If not, where is >it and how are you going to install it? Can bzip run standalone or must >the O/S be installed in order for bzip to work? > >Whether a backup fits on one tape or two is one of the LAST things to >worry about! If I haven't responded before, I do it now. VERY WELL STATED! David
From: Richard B. Gilbert on 18 Mar 2010 09:35 AZ Nomad wrote: > On Wed, 17 Mar 2010 04:15:26 +0000 (UTC), David Combs <dkcombs(a)panix.com> wrote: >>> There is much to be said for taking your backup to a test system, >>> booting that system from CD/DVD and actually restoring your file >>> systems! If you do this, you will KNOW that you CAN do this. Or if >>> things do not go well, you KNOW that you CAN'T restore successfully and >>> that you will need to take corrective action. >>> >>> You DO NOT want to become the guy who could not restore his employer's >>> accounts receivable! That could mean that your only recourse is to >>> attend "Hamburger University" and get a job managing a McDonald's! >>> >>> And it's not JUST accounts receivable. Files of many sorts can and >>> probably will contain business critical information. >>> >>> Consider whether the extra time to "unbzip" before you can restore is >>> going to be critical. Is bzip on the install CD/DVD? If not, where is >>> it and how are you going to install it? Can bzip run standalone or must >>> the O/S be installed in order for bzip to work? >>> >>> Whether a backup fits on one tape or two is one of the LAST things to >>> worry about! > >> If I haven't responded before, I do it now. > >> VERY WELL STATED! > not really. > > A company with an employer's accounts receivables worth more than the > price of a tape drive will have the resources to assemble a running > solaris system. In reality, it'll have a system ready to take over > in a moment's notice in case of hardware failure of the primary system. > > No need to boot off optical media. No need to have less than a full > system. > Well, maybe! Some companies can and do have a hardware configuration and software that allows another system to "step in and pick up the load." You'd better believe that it's not cheap! When the towers fell back in 2001, Merrill-Lynch was off line for a whole four minutes while they "failed over" to a backup data center a few miles away. They didn't lose a single transaction or a byte of data. I suspect that we could all party wildly for the rest of our lives and have money left over for the money that must have cost! Many would find it far less expensive to be off line for four hours or four days. Some of us may remember the days when, if power went off, the cash register was cranked by hand! You don't see many of those any longer. It's all done by computer now and God help us if the computers fail.
From: David Combs on 25 Mar 2010 02:31
In article <kd6dnZe-Xs4mRz3WnZ2dnUVZ_vOdnZ2d(a)giganews.com>, Richard B. Gilbert <rgilbert88(a)comcast.net> wrote: >AZ Nomad wrote: >It's all done by computer now and God help us if the computers fail. That's right -- it's ALL done by computer -- witness the Prius and its problems. God help us is someone does a Dr. Strangelove via a 50MTon or several exploding what, 50 miles up over the U.S., frying 60 jillion chips. We'd all starve to death -- trucks, cars, trains, power-plants, switching- stations -- NOTHING would work. Ditto for all the radios, battery-powered ones too -- all dead. Thus no way to even FIND OUT what happened! David |