I've never had a real need for an LVM. When I replace my machine every 3 years, I buy a bigger disk and make bigger partitions. It's seldom that I'm really squeezed for space in any partition.
SteveT On Saturday 02 April 2011 17:50:55 William L. Thomson Jr. wrote: > Let me start with this > > "The levels of indirection that volume managers introduce can complicate > the boot process and make disaster recovery difficult, especially when > the base operating-system and other essential tools are themselves on an > LV." > http://en.wikipedia.org/wiki/Logical_volume_management#Disadvantages > > On Sat, 2011-04-02 at 17:07 -0400, Kyle Gonzales wrote: > > Most enterprise class hardware is sourced from Dell, HP, IBM or Sun. > > There are others as well, that make very large systems, Cray, SGI, etc. > > > A feature that all of these cards share is the ability to boot from > > remote media, some even have the ability to store a boot or rescue disk. > > > > These cards are the "remote hands" for the enterprise IT admin. > > > > When it is necessary to use this feature, it is rarely because someone > > munged an LVM configuration file. So yes, your solution is valid if the > > only concern someone has is that they messed up LVM. That is a very > > narrow use case. > > There could be many others reasons or causes of failures. But the point > remains if you can avoid using a rescue disk, in any form. That usually > will save you time in recovery. Since no matter what form of rescue you > use to boot, you will manually be mounting / and performing other > operations manually. Rescue media just ads more steps. If you have to > use it then you do. But if you can avoid it, it will save steps and > time. > > > If you are breaking out many partitions from /, then perhaps you are > > fortunate enough to have a small root partition. I will still maintain > > that it introduces needless complexity for the problem you are trying to > > solve. > > Unless the entire system is very small like VMs, which consist of a > single partition. Any host machine, will usually have a very small root > partition. With other things broken out onto their own, and typically > being LVMs. > > > > Thus there is no benefit to having partitions on lvm that do not change > > > in size and may never. Just becomes a potential liability and requires > > > the system to need things like a rescue disk to recover the system. Not > > > to mention some to supply that rescue disk. Unless you leave one in > > > every machine :P > > > > I am sorry, William, but this is completely and totally false. There > > are many reason to use LVM for all your partitions (save /boot, until > > GRUB2 becomes more commonly used). > > You just contradicted yourself in that same statement. I am only talking > about using it for two partitions, and till your using grub2. You still > have to have a non LVM /boot partition. So your saving the creation of > one partition. Not seeing why that is such a big deal, one vs two. > > > Here are just a few use cases from > > > > Wikipedia: http://en.wikipedia.org/wiki/Logical_Volume_Manager_(Linux) > > > > * Managing large hard disk farms by letting you add disks, replace > > disks, copy and share contents from one disk to another without > > disrupting service. > > I could see this one as being a valid use case, replacing the disk / is > on. Though if thats a raided partition to begin with. Which is normally > the case for any enterprise storage hardware, or even non-enterprise > storage. Then there is no benefit. I can go replace disks now, and I > don't need LVM at all :) > > > * Making backups by taking "snapshots." > > What is the difference between a snapshot and making a tarball of /? If > its contents are not changing, there is no difference. Which / contents > rarely change if other things are on their own partition. > > Sure you can turn around and mount a snapshot and do stuff with that. > But you can do the same by unpacking the tarball on a temporary lvm. Its > not like you can switch the partition / is on with a live system. Go > from one lvm / to a snapshot and the back. > > > * Creating single logical volumes of multiple physical volumes or entire > > hard disks (somewhat similar to RAID 0, but more similar to JBOD), > > allowing for dynamic volume resizing. > > Again who is going to resize /? If everything else is on its own > partition? Its been a long time Unix rule of thumb to put things on > their own partition for many reasons. That does not go out the window > when it comes to LVM. Now I guess you could combined two raided devices > into a singe LVM. But thats pretty excessive for /. > > > An additional recent use case for LVM is whole disk encryption using > > dm-crypt: http://en.wikipedia.org/wiki/Dm-crypt > > That does not depend on lvm. You can use dm-crypt even if your not using > LVM. No case point is being made there. > > > The only current caveat is the inability for GRUB1 to boot from LVM, > > requiring /boot to not be hosted on LVM. GRUB2 removes this limitation. > > When will RHEL ship with Grub2? Very few distros are shipping that now, > and that includes Gentoo. However some are using grub2 already. --------------------------------------------------------------------- Archive http://marc.info/?l=jaxlug-list&r=1&w=2 RSS Feed http://www.mail-archive.com/[email protected]/maillist.xml Unsubscribe [email protected]
