----- Original Message ----- | On Sat, Feb 28, 2015 at 4:28 PM, James A. Peltier <jpeltier at sfu.ca> wrote: | | > People who understand how to use the system do not suffer these problems. | > LVM adds a bit of complexity for a bit of extra benefits. You can't | > blame LVM for user error. Not having monitoring in place or backups is a | > user problem, not an LVM one. | | It's a good point. Suggesting the OP's problem is an example why LVM | should not be used, is like saying dropped laptops is a good example | why laptops shouldn't be used. | | A fair criticism is whether LVM should be used by default with single | disk system installations. I've always been suspicious of this choice. | (But now, even Apple does this on OS X by default, possibly as a | prelude to making full volume encryption a default - their "LVM" | equivalent implements encryption as an LV level attribute called | logical volume family.) | | -- | Chris Murphy There is no difference between a single disk system and a multi-disk system in terms of being able to dynamically resize volumes that reside on a volume group. Having the ability to resize a volume to be either larger or smaller on demand is a really nice feature to have. Did you make / too small and have space on home and you're using ext3/4 then simply resize the home logical volume to be smaller and all the free extents to /. Pretty simple process really and it can be done online. This is just one example. There are others, but this has nothing to do with the OP. Getting back to the OP, it would seem that you may be stuck in a position where you need to restore from backup. Without having further details into what exactly is happening I fear you're not going to be able to recover. I'd be available to talk off list if needed. -- James A. Peltier IT Services - Research Computing Group Simon Fraser University - Burnaby Campus Phone : 778-782-6573 Fax : 778-782-3045 E-Mail : jpeltier at sfu.ca Website : http://www.sfu.ca/itservices Twitter : @sfu_rcg Powering Engagement Through Technology "Build upon strengths and weaknesses will generally take care of themselves" - Joyce C. Lock
On Sat, Feb 28, 2015 at 5:59 PM, James A. Peltier <jpeltier at sfu.ca> wrote:> There is no difference between a single disk system and a multi-disk system in terms of being able to dynamically resize volumes that reside on a volume group. Having the ability to resize a volume to be either larger or smaller on demand is a really nice feature to have.I'll better qualify this. For CentOS it's a fine default, as it is for Fedora Server. For Workstation and Cloud I think LVM overly complicates things. More non-enterprise users get confused over LVM than they ever have a need to resize volumes.> Did you make / too small and have space on home and you're using ext3/4 then simply resize the home logical volume to be smaller and all the free extents to /. Pretty simple process really and it can be done online.XFS doesn't support shrink, only grow. XFS is the CentOS 7 default. The main advantage of LVM for CentOS system disks is ability to use pvmove to replace a drive online, rather than resize. If Btrfs stabilizes sufficiently for RHEL/CentOS 8, overall it's a win because it meets the simple need of mortal users and supports advanced features for advanced users. (Ergo I think LVM is badass but it's also the storage equivalent of emacs - managing it is completely crazy.)>This is just one example. There are others, but this has nothing to do with the OP. > > Getting back to the OP, it would seem that you may be stuck in a position where you need to restore from backup. Without having further details into what exactly is happening I fear you're not going to be able to recover. I'd be available to talk off list if needed.Yeah my bad for partly derailing this thread. Hopefully the original poster hasn't been scared off, not least of which may be due to my bark about cross posting being worse than my bite. -- Chris Murphy
Dear Chris, James, Valeri and all, Sorry to have not responded as I'm still on struggling with the recovery with no success. I've been trying to set up a new system with the exact same scenario (4 2TB hard drives and remove the 3rd one afterwards). I still cannot recover. We did have a backup system but it went bad for a while and we did not have replacement on time until this happened. From all of your responses, it seems, recovery is almost impossible. I'm now trying to look at the hardware part and get the damaged hard drive to fixed. I appreciate all you helps and still wait and listen to more suggestions. Regards, Khem On 03/01/2015 08:40 AM, Chris Murphy wrote:> On Sat, Feb 28, 2015 at 5:59 PM, James A. Peltier <jpeltier at sfu.ca> wrote: >> There is no difference between a single disk system and a multi-disk system in terms of being able to dynamically resize volumes that reside on a volume group. Having the ability to resize a volume to be either larger or smaller on demand is a really nice feature to have. > I'll better qualify this. For CentOS it's a fine default, as it is for > Fedora Server. For Workstation and Cloud I think LVM overly > complicates things. More non-enterprise users get confused over LVM > than they ever have a need to resize volumes. > >> Did you make / too small and have space on home and you're using ext3/4 then simply resize the home logical volume to be smaller and all the free extents to /. Pretty simple process really and it can be done online. > XFS doesn't support shrink, only grow. XFS is the CentOS 7 default. > The main advantage of LVM for CentOS system disks is ability to use > pvmove to replace a drive online, rather than resize. If Btrfs > stabilizes sufficiently for RHEL/CentOS 8, overall it's a win because > it meets the simple need of mortal users and supports advanced > features for advanced users. (Ergo I think LVM is badass but it's also > the storage equivalent of emacs - managing it is completely crazy.) > >> This is just one example. There are others, but this has nothing to do with the OP. >> >> Getting back to the OP, it would seem that you may be stuck in a position where you need to restore from backup. Without having further details into what exactly is happening I fear you're not going to be able to recover. I'd be available to talk off list if needed. > Yeah my bad for partly derailing this thread. Hopefully the original > poster hasn't been scared off, not least of which may be due to my > bark about cross posting being worse than my bite. >