[Mageia-dev] time to switch from raw partitions to lvm?

Thu Feb 24 06:06:27 CET 2011

Thierry Vignaud a écrit :
+>
+> On 21 February 2011 08:51, P. Christeas<p_christ at hol.gr>  wrote:
+>>> What do you think about switching from defaulting to installing on raw
+>>> partitions to lvm
+>>> installing on LVs like fedora does ?
+>>
+>> I vote against that. (=to be enabled by default)
+>>
+>> LVM is fine for "enterprise" setups, or better, installations where the
+>> (expert) admin will need to resize/move partitions in the future. But, for
+>> simple machines/users, the complexity of having LVM is IMHO not worth it.
+>>
+>> (remember also that on all *nix OSes, you can just add a partition, move some
+>> files like /usr/share/doc into it and then mount it on /usr/share/doc, thus
+>> freeing /usr of some space. No LVM, no virtualization, no ZFS required)
+>
+> It's not as easy as LVM (need to use a partitionner).
+> Diskdrake and the like will force you to umount the partitions to resize
+> which may needs to boot on a rescue CD (eg for resizing / fs)
+> It may not be possible ie:
+
+A rescue CD like Sysrescuecd is easy to use and comes with all the tools 
+needed.
+It would be nice if the rescue option of the eventual release Mageia 
+dvds contained the few utilities necessary for this.
+
+> - you already have 4 primary partitions and none of them is an extended one.
+
+A gpt partition table solves this problem.
+Standard gpt allows 128 partitions in less space than is typically used 
+with an mbr partition table with an extended partition.
+As well, there is a backup partition table at the end of the disk, so it 
+is inherently more reliable.
+
+> - If you've a small 8Go partition at start of the disk followed by one
+> To partition
+>    and you want to increase the first one, you're screwed without LVM
+>    With LVM, you can just got some free space from anywhere (even another disk)
+
+You can do that with symbolic links if you don't want to resize the 
+partitions.  Although I wouldn't partition a disk like that in the first 
+place.  (I prefer dividing a disk into a least several partitions.  I 
+have 8 on my current system.)
+
+> What's more, one gains many features:
+>
+> - snapshots (yes snapshots for sql db backups are not for end users) but still
+>    usefull for saving the whole system at one fixed time
+>
+> - you can extend some filesystems from space from other disks
+>
+> - it's easier to add space where needed when defaults partitions sizing proved
+>    to be altered after some usage
+>
+> - one can live resize (w/o umouting/remounting)
+>
+> - one can use snapshots in order to rollback dangerous update
+>    (eg: for trying initscript ->  systemd switch, ...)
+>
+> I think it brings many usefull features.
+> Those who don't want LVM could still do manual partitionning.
+
+These seem to be mostly enterprise-oriented factors, unless I'm missing 
+something.
+For now at least, I prefer manual partitionning to be the default.
+
+-- 
+André
+