Converting an ext3 filesystem to ext4
in [General Linux]
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From: Balwinder S Dheeman on 4 Jul 2010 01:53 On 07/04/2010 05:12 AM, mjt wrote: > On Sat, 03 Jul 2010 14:51:02 -0400 > despen(a)verizon.net wrote: > > [snipped] >> I must have missed that part of the requirement. >> The file system is converted to ext4. >> That meets the subject line requirement. >> >> If the filesystem takes on even more ext4 attributes as it >> get's written to, I fail to see a problem. > > The OP stated, "Does it mean that I'll have a full ext4 > filesystem only *after* "the online defrag tool" has > finished its job?" No, the ext4 is backward compatible with ext2 and ext3 whereas the ext3 is also somewhat forward compatible with ext4. The users however, will lose this compatibility as soon as they start using some of ext4 features including 'extents'. > IOW, they want to know if all the files in the filesystem > will be true ext4 files (w/extents) - that's how I read > it anyway :) So, it's not just that they want to know > how to convert ext3->4, but they want clarification about > a statement the OP found in a tech article about conversion. No, as others also stated that a best and, or only way to switchover to a true ext4 file-system is create a fresh one. -- Balwinder S "bdheeman" Dheeman Registered Linux User: #229709 Anu'z Linux(a)HOME (Unix Shoppe) Machines: #168573, 170593, 259192 Chandigarh, UT, 160062, India Plan9, T2, Arch/Debian/FreeBSD/XP Home: http://werc.homelinux.net/ Visit: http://counter.li.org/
From: Kevin the Drummer on 4 Jul 2010 23:26 mjt <myswtestYOURSHOES(a)gmail.com> wrote: > On 03 Jul 2010 08:12:35 GMT > HamRadio <toglimi.hamradio(a)toglimi.quipo.it> wrote: > > > I'd like to convert my ext3 filesystem to ext4 > > For what reason(s)? What is it you need from > ext4 that ext3 is not offering? Don't know about the OP. But, I want ext4 over ext3 for the big improvement in fsck time. Thanks.... -- PLEASE post a SUMMARY of the answer(s) to your question(s)! Unless otherwise noted, the statements herein reflect my personal opinions and not those of any organization with which I may be affiliated.
From: John Reiser on 6 Jul 2010 09:57 On 07/03/2010 08:14 AM, Kenny McCormack wrote: > In article <17qdnZ7dk6QP3LLR4p2dnAA(a)giganews.com>, > John Reiser <jreiserfl(a)comcast.net> wrote: > ... >> If you cannot afford to buy or borrow such an "extra" drive, >> then you certainly cannot afford to scribble all your data. >> Asking questions like you did strongly suggests a non-ignorable >> probability that you *WILL* scribble *ALL* your data. > > It is attitudes and posts like this that show why MS is beating Linux in > most markets. NTFS comes with a simple utility that works that converts > FAT to NTFS (in place). Linux would do well to emulate that. WinXP and Win7 have a Microsoft utility diskmgmt.msc which manipulates filesystems and partitions. I asked it to delete only the last partition (in this case, partition number 8, a logical drive in the Extended partition on a harddrive with a Basic (DOS, not GPT) disk label). Diskmgmt.msc deleted the last THREE partitions. So much for the reliability of MS disk utilities. I had to re-create the other two partitions by hand using fdisk and block counts which I reconstructed from dim memory. If *you* do not understand and have confidence in some utility program which manipulates partitions or whole filesystems, then you should not use it. The Original Poster was in such a situation. Asking the 'net is one way to try to gain some understanding and confidence. Using a procedure which takes a fresh backup is better. Verifying the backup and testing the restore procedure is better yet. --
From: mjt on 6 Jul 2010 13:26 On Tue, 06 Jul 2010 09:41:06 -0700 John Reiser <jreiserfl(a)comcast.net> wrote: > >> If it runs this job automatically, when this happens? > > > > I'm not sure what "online defrag" tool they're talking about. > > When extents are enabled with tune2fs, new files will have > > extents attributes associated ... pre-conversion files will > > be read and written in a transparent manner. > > > > Maybe they're talking about e4defrag or shake or defrag? > > It is straightforward to convert from the ext3 on-disk format to the > ext4 on-disk format, using NO defragmentation at all. I guess no one "get's it" - what I've said. I'll try again, but I guess someone *else* will explain how to convert from ext3 to ext4 ... maybe ONE MORE explanation will work :) I was responding to the OP's original request whether the conversion of an ext3 filesystem will, in the end, be a 100% ext4 filesystem. IT WILL NOT. All new files (after the conversion) will be considered a "100% ext4 file" ... files before the conversion will be read and written in a transparent manner, but not have ext4-specific attributes. The only way to truly have all files exist as true "ext4 files", the filesystem will have to be off-loaded, the filesystem converted to ext4, then the files will then need to be copied back. You *could* run a defrag utility (because the defrag utility will re-write a file back to disk in a contiguous manner) ... but since the defrag utility may bypass numerous files not fragmented, any of those files not re-written will not be considered a "100% ext4" file. -- This login session: $13.99, but for you $11.88 <<< Remove YOURSHOES to email me >>>
From: Chris Davies on 6 Jul 2010 19:05
>> I'd like to convert my ext3 filesystem to ext4 but I've read here: John Reiser <jreiserfl(a)comcast.net> wrote: > You might try some experiments using a spare USB2.0 flash memory drive. I've done this sort of experiment in the past by creating an ondisk file and then mounting that as a loopback. dd if=/dev/zero of=/var/tmp/bigfile bs=1000m count=10000 # 10G L=$(losetup --show -f /var/tmp/bigfile); echo $L # Loopback dev mkfs -t ext3 "$L" mount "$L" /mnt Chris |