I'm planning to give the Reiser FS a run-in (or should that be ruin?) and I have a few questions I'd be grateful to get advice on: 1) Is the reiser support in 7.2 (2.4.4-4GB) safe? I'm not intending to upgrade my kernel anytime soon. 2) How does it get set up in /etc/fstab? Is it just a matter of changing ext2 to reiserfs? 3) What's this I hear about tail and notail modes? I notice that mkreiserfs has a '-v format' option which can be either 1 or 2 but it explains nothing about what these mean. Thanks, -- Tim Harrell <tim.harrell@ntlworld.com>
On Thursday 06 December 2001 22.21, Tim Harrell wrote:
2) How does it get set up in /etc/fstab? Is it just a matter of changing ext2 to reiserfs?
Yes, except you should have a notail as an option.
3) What's this I hear about tail and notail modes? I notice that mkreiserfs has a '-v format' option which can be either 1 or 2 but it explains nothing about what these mean.
-v is the version of reiserfs used. notail isn't an option to mkreiserfs, it is an option to mount. When you normally use reiser it will store small files and ends of larger files together in blocks to optimize space usage. Compare this to ext2 where is you have a 4k block size and store a 1k file you simply lose 3k. With reiser you can store 4 files of 1k each and it will use 4k. The problem is with the /boot directory. lilo loads before the kernel and doesn't use a file system at all. This is why you have to rerun lilo every time you make a change to your kernel or initrd. It creates a map describing exactly where on the hd the kernel and initial ramdisk is stored. This system couldn't handle the reiserfs way of storing "tails" and small files, so you had to use "notail" as a mount option to /boot (or / if you didn't have /boot as a separate partition). I don't know if it's later versions of lilo or later versions of reiser that fixed it, but now there shouldn't be a problem with having /boot as a normal reiser partition. With 7.2 I think you did, but memory fails me a bit. regards Anders
On Thursday 06 Dec 2001 9:32 pm, Anders Johansson wrote:
On Thursday 06 December 2001 22.21, Tim Harrell wrote:
2) How does it get set up in /etc/fstab? Is it just a matter of changing ext2 to reiserfs?
Yes, except you should have a notail as an option.
Thanks Anders, What about the fs_passno field (the final one)? Is this relevant for a JFS or should I just change it to zero?
3) What's this I hear about tail and notail modes? I notice that mkreiserfs has a '-v format' option which can be either 1 or 2 but it explains nothing about what these mean.
-v is the version of reiserfs used. notail isn't an option to mkreiserfs, it is an option to mount. When you normally use reiser it will store small files and ends of larger files together in blocks to optimize space usage. Compare this to ext2 where is you have a 4k block size and store a 1k file you simply lose 3k. With reiser you can store 4 files of 1k each and it will use 4k.
I'll probably use the notail option given what you've said.
The problem is with the /boot directory. lilo loads before the kernel and doesn't use a file system at all. This is why you have to rerun lilo every time you make a change to your kernel or initrd. It creates a map describing exactly where on the hd the kernel and initial ramdisk is stored. This system couldn't handle the reiserfs way of storing "tails" and small files, so you had to use "notail" as a mount option to /boot (or / if you didn't have /boot as a separate partition).
I don't know if it's later versions of lilo or later versions of reiser that fixed it, but now there shouldn't be a problem with having /boot as a normal reiser partition. With 7.2 I think you did, but memory fails me a bit.
regards Anders
Cheers. I'm not switching /boot to reiser, just going to migrate the other stuff bit by bit (starting with a scratch partition). I'm aware of the need to loader reiser in the ramdisk to be able to allow LILO to work with it, if I ever need to do that. One other point - are there issues with dump/restore or tools like dd? -- Tim Harrell <tim.harrell@ntlworld.com>
On Thursday 06 December 2001 22.43, Tim Harrell wrote:
What about the fs_passno field (the final one)? Is this relevant for a JFS or should I just change it to zero?
zero means that fsck won't touch it at all. Don't do that. reiser needs an fsck pass even if it's just replaying a log.
I'll probably use the notail option given what you've said.
Only on /boot. Don't do it on /
Cheers. I'm not switching /boot to reiser, just going to migrate the other stuff bit by bit (starting with a scratch partition). I'm aware of the need to loader reiser in the ramdisk to be able to allow LILO to work with it, if I ever need to do that.
No no. having reiser in the initrd is only needed if 1) you have reiser as a module as opposed to compiled statically in the kernel (the default in suse) and 2) you have reiser on /
One other point - are there issues with dump/restore or tools like dd?
Yes, they don't work at all. There is a dump for XFS I think, but AFAIK none for reiser. Anders
On Thursday 06 Dec 2001 9:50 pm, Anders Johansson wrote:
On Thursday 06 December 2001 22.43, Tim Harrell wrote:
I'll probably use the notail option given what you've said.
Only on /boot. Don't do it on /
Sorry, Anders. I'm getting a little confused. Are you saying that I should not use notail, except on /boot? My problem is I do not have an actual /boot partition, it just lives under root. notail is supposed to be a lot quicker isn't it?
No no. having reiser in the initrd is only needed if 1) you have reiser as a module as opposed to compiled statically in the kernel (the default in suse) and 2) you have reiser on /
OK, I take it I have it native in the kernel for 7.2 then, and that I can forget about loading reiser in initrd (I'm not intending to make / a reiser fs just yet). Regards, -- Tim Harrell <tim.harrell@ntlworld.com>
On Thursday 06 December 2001 23.10, Tim Harrell wrote:
Only on /boot. Don't do it on /
Sorry, Anders. I'm getting a little confused. Are you saying that I should not use notail, except on /boot? My problem is I do not have an actual /boot partition, it just lives under root. notail is supposed to be a lot quicker isn't it?
You only need notail on a reiserfs partition that holds /boot.
No no. having reiser in the initrd is only needed if 1) you have reiser as a module as opposed to compiled statically in the kernel (the default in suse) and 2) you have reiser on /
OK, I take it I have it native in the kernel for 7.2 then, and that I can forget about loading reiser in initrd (I'm not intending to make / a reiser fs just yet).
I'm sorry, my paranthesis got a little misplaced. The default in suse is to have it as a module, so if you make / a reiserfs partition you'll need to have it in initrd. regards Anders
On Thursday 06 Dec 2001 10:14 pm, Anders Johansson wrote:
On Thursday 06 December 2001 23.10, Tim Harrell wrote:
Only on /boot. Don't do it on /
Sorry, Anders. I'm getting a little confused. Are you saying that I should not use notail, except on /boot? My problem is I do not have an actual /boot partition, it just lives under root. notail is supposed to be a lot quicker isn't it?
You only need notail on a reiserfs partition that holds /boot.
No no. having reiser in the initrd is only needed if 1) you have reiser as a module as opposed to compiled statically in the kernel (the default in suse) and 2) you have reiser on /
OK, I take it I have it native in the kernel for 7.2 then, and that I can forget about loading reiser in initrd (I'm not intending to make / a reiser fs just yet).
I'm sorry, my paranthesis got a little misplaced. The default in suse is to have it as a module, so if you make / a reiserfs partition you'll need to have it in initrd.
regards Anders
Ok, I think the fog is clearing now. I don't need to load the reiser modules as I'm not using Reiser on / (and hence anything in /boot either), it *is* a module and not in the stock kernel however. Good. I also don't *have* to put notail as a mount option, for reasons explained. However, I hear that notail is a fair bit quicker so I guess there's no harm in me using it anyway? (if I can live with the extra fragmentation, as I've lived with it on ext2!) Cheers, -- Tim Harrell <tim.harrell@ntlworld.com>
On Thursday 06 Dec 2001 9:50 pm, Anders Johansson wrote:
On Thursday 06 December 2001 22.43, Tim Harrell wrote:
What about the fs_passno field (the final one)? Is this relevant for a JFS or should I just change it to zero?
zero means that fsck won't touch it at all. Don't do that. reiser needs an fsck pass even if it's just replaying a log.
Anders
I checked the FAQ on namesys and it says the 5th/6th fields should be 0 0 (Q:28).
From the FAQ:
Why are ReiserFS filesystems not fscked on reboot after a crash? Because ReiserFS provides journalling of meta-data. After a crash, the consistency of a filesystem is restored by replaying the transaction log. Regards, -- Tim Harrell <tim.harrell@ntlworld.com>
On Friday 07 December 2001 13.05, Tim Harrell wrote:
I checked the FAQ on namesys and it says the 5th/6th fields should be 0 0 (Q:28).
From the FAQ:
Why are ReiserFS filesystems not fscked on reboot after a crash? Because ReiserFS provides journalling of meta-data. After a crash, the consistency of a filesystem is restored by replaying the transaction log.
A truth to be taken with a grain of salt. I've had a reiser go corrupt on me, where I had to run reiserfsck. And SuSE's default installation is to have a number in fs_passno same as for ext2. On the other hand they have a number in dump too, and there is no dump, so I don't really know the rationale. And rethorically: if there's no need for fsck, why did they bother making one? //Anders
One other point - are there issues with dump/restore or tools like dd?
Yes, they don't work at all. There is a dump for XFS I think, but AFAIK none for reiser.
There is no real dump. But if you want a dump look-alike, which supports dump levels from 0-9 and uses tar as the backend, you may want to consider the reiserfsdump wrapper script at http://marcel.wanda.ch/Source/#reiserfsdump I would not recommend using dd for a backup, except when the partition is unmounted. Even then, only if you want to waste extra space (dd dumps the unused areas as well, which might contain uncompressible garbage) for the sake of read speed.
You only need notail on a reiserfs partition that holds /boot.
With newer versions of lilo (e.g., what is included with 7.3), notail is no longer required. -Marcel
Marcel Waldvogel wrote:
One other point - are there issues with dump/restore or tools like dd?
Yes, they don't work at all. There is a dump for XFS I think, but AFAIK none for reiser.
dd doesn't care what fs is used. It will copy filesystems just fine. -- Mark Hounschell dmarkh@cfl.rr.com
On Tuesday 05 March 2002 12.18, Mark Hounschell wrote:
Marcel Waldvogel wrote:
One other point - are there issues with dump/restore or tools like dd?
Yes, they don't work at all. There is a dump for XFS I think, but AFAIK none for reiser.
dd doesn't care what fs is used. It will copy filesystems just fine.
http://lists.suse.com/archive/suse-linux-e/2001-Dec/0660.html How do old threads get new life? //Anders
On Tue, Mar 05, 2002 at 06:18:17AM -0500, Mark Hounschell wrote:
One other point - are there issues with dump/restore or tools like dd? Yes, they don't work at all. There is a dump for XFS I think, but AFAIK none for reiser.
Marcel Waldvogel wrote: dd doesn't care what fs is used. It will copy filesystems just fine.
Yes (see the message you replied to). For copying betweeen reasonably-full same-size disks, dd is probably the best. For backups, it probably isn't. And for reiserfs, you should be very careful not to dd off a mounted file system. The normal mount procedure will not detect that some blocks were copied at different times and might thus be inconsistent. -Marcel
On Tuesday 05 March 2002 11.07, Marcel Waldvogel wrote:
One other point - are there issues with dump/restore or tools like dd?
Yes, they don't work at all. There is a dump for XFS I think, but AFAIK none for reiser.
There is no real dump. But if you want a dump look-alike, which supports dump levels from 0-9 and uses tar as the backend, you may want to consider the reiserfsdump wrapper script at http://marcel.wanda.ch/Source/#reiserfsdump
I would not recommend using dd for a backup, except when the partition is unmounted. Even then, only if you want to waste extra space (dd dumps the unused areas as well, which might contain uncompressible garbage) for the sake of read speed.
You only need notail on a reiserfs partition that holds /boot.
With newer versions of lilo (e.g., what is included with 7.3), notail is no longer required.
Yeah, unfortunately my psychic powers were failing me when I wrote that mail, which was when 7.2 was current (or was it 7.1, even. Memory fails me in my old age). //Anders
Il 22:21, giovedì 6 dicembre 2001, Tim Harrell ha scritto:
I'm planning to give the Reiser FS a run-in (or should that be ruin?) and I have a few questions I'd be grateful to get advice on:
1) Is the reiser support in 7.2 (2.4.4-4GB) safe? I'm not intending to upgrade my kernel anytime soon.
I have been experiencing some problem with wtmp files which gets corrupted. I have heard about someone else having the same problem, so I would not advice you to use reiserfs in /var Praise
participants (5)
-
Anders Johansson -
Marcel Waldvogel -
Mark Hounschell -
Praise -
Tim Harrell