On 12/11/10 2:04 PM, Michael Miles wrote: > Patrick O'Callaghan wrote: >> On 12/11/10 1:13 PM, Michael Miles wrote: >>> Considering that the LVM is a ext4 Virtual partition it seems to me >>> that it would be easy to convert but there is no such beast out there >>> Lots of stuff for converting ext3 to ext4 but nothing for what I need. >> >> This is pure speculation on my part, but I'm guessing one reason it's >> hard is that the LVM layer knows nothing about the ext4 layer. The >> ext4 layer contains lots of metadata (inodes, freelists, etc.) which >> includes pointers to disk sectors or extents. In a physical partition >> these point to real disk addresses but in an LVM partition they are >> virtual (compare real with virtual memory for an analogy). From LVM's >> viewpoint the entire ext4 fs is just disk sectors with random binary >> data. The fact that some of this stuff is fs metadata and some isn't >> means that a conversion tool would need to understand the ext4 >> metadata to convert it. Of course if it's ext3 or xfs or btrfs etc. >> then the same applies, with different rules for each one. >> >> Worse still, if you want a in-place conversion you have to be able to >> do this in such a way that it's recoverable even after a hard system >> crash in the middle of the conversion. And if you don't need it >> in-place, you already have the solution as said before. >> >> Just my 2 cents. >> >> poc > Agreed, I am just really surprised that Fedora would adopt this method > of storage as it slows down the drive by a huge margin. > That reason alone would say to me' No, don't want this" Perhaps there are other benchmarks with different results, I don't know. In any case, Fedora presumably decided that the gain in flexibility was worth it. The irony is that there *is* a considerable gain for people with large systems, server farms, clusters and what have you. For the ordinary desktop user it's much more open to question, particularly as some tools (notably parted) don't support it. Case in point: my F13 LVM layout suffered a number of changes during its life, basically because I needed to expand / at the expense of /home. The upshot was that the LV containg / was physically (but not logically) split in two non-contiguous regions. Then I decided to expand the /boot partition, which of course is not in LVM. This meant resizing /, freeing space at the end of the disk and moving the physical partition where LVM lived, but of course parted refused since it doesn't understand LVM. I consulted Google, and this list, and a very knowledgeable friend, and the LVM docs, and concluded that there was no avoiding messing with the disk partition table via fdisk. Needless to say I lost everything. Luckily I have a nightly backup to a NAS so the day was saved, and I then got to do a completely clean install of F14. So maybe LVM is a Good Thing after all :-) poc -- users mailing list users@xxxxxxxxxxxxxxxxxxxxxxx To unsubscribe or change subscription options: https://admin.fedoraproject.org/mailman/listinfo/users Guidelines: http://fedoraproject.org/wiki/Mailing_list_guidelines
