ext4 on current?

grissiom · 03-10-2009, 06:59 PM

There is a huge update on the current branch and I'm happy playing with it now. I noticed that it upgraded to new kernel and tool chains which may provide ext4 on it. How to creat/convert a partition to ext4 painlessly? What issues should I care about?

Thanks in advance~

Daedra · 03-10-2009, 07:13 PM

Well what I did, at least for a fresh install of 12.2, was download partedmagic and I burned it on the ISO, then I rebooted and booted partedmagic and made my ext4 partition for slack with the gparted utility. The I rebooted using the slackware 12.2 install DVD. However before you run setup you must set the test filesystem flag for ext4 otherwise it will fail half way through the install. After you log in as root BEFORE you run "setup" run this command "tune2fs -E test_fs /dev/*wahteveryourdiscis* so my system for instance my slack drive is the second sata drive in my system so my command would be

tune2fs -E test_fs /dev/sdb1

After that run setup and slack should install fine on your new ext4 partiton.

oh one more thing! when the install utility asks if you want to format your linux partition select "no, and continue".

The default slack kernel is 2.6.27 kernel so after i installed I compiled my own 2.6.28 kernel for better ext4 support.

GOOD LUCK.

Alien Bob · 03-11-2009, 03:31 AM

Quote:

Originally Posted by grissiom

There is a huge update on the current branch and I'm happy playing with it now. I noticed that it upgraded to new kernel and tool chains which may provide ext4 on it. How to creat/convert a partition to ext4 painlessly? What issues should I care about?

Thanks in advance~

The installer in slackware-current supports ext4 now, it is even the default filesystem type when formatting a partition. Mounting an ext3 filesystem as ext4 will enable certain new features that remain compatible with ext3, so that you can re-mount it as ext3 later (see also the previous post and google will show you a lot of tutorials). Converting an existing ext3 to ext4 is not hard (you should not have this partition mounted). When you want to enable the new "file-extents" feature of ext4:

Code:

# tune2fs -O extents,uninit_bg,dir_index /dev/yourdevice
# fsck -pf /dev/yourdevice

but after conversion, only your new files will benefit most of extents while your existing files will keep using the old ext3 data structures. Once you run this tune2fs command on the ext3 partition, you will not be able to mount it as ext3 again. This is unlike ext2 <=> ext3 where you could mount an ext3 partition as ext2 and only lose the journal.

Eric

C-Sniper · 03-12-2009, 12:38 AM

Quote:

Originally Posted by Alien Bob

The installer in slackware-current supports ext4 now, it is even the default filesystem type when formatting a partition. Mounting an ext3 filesystem as ext4 will enable certain new features that remain compatible with ext3, so that you can re-mount it as ext3 later (see also the previous post and google will show you a lot of tutorials). Converting an existing ext3 to ext4 is not hard (you should not have this partition mounted). When you want to enable the new "file-extents" feature of ext4:

Code:

# tune2fs -O extents,uninit_bg,dir_index /dev/yourdevice
# fsck -pf /dev/yourdevice

but after conversion, only your new files will benefit most of extents while your existing files will keep using the old ext3 data structures. Once you run this tune2fs command on the ext3 partition, you will not be able to mount it as ext3 again. This is unlike ext2 <=> ext3 where you could mount an ext3 partition as ext2 and only lose the journal.

Eric

Awesome.
Glad to see the support being added.
Thanks for the update Eric!

Stroker · 03-12-2009, 01:09 AM

Ext4 can have up to 2.5 minutes of delay before writing to disk, causing some potential problems if the system crashes.

Ubuntu Bug #317781

Where as Ext3 writes to disk every 5 seconds.

grissiom · 03-12-2009, 01:22 AM

Thanks Daedra and Eric ~ From your posts I know current Slackware have full ext4 support. So I will format the WinXp partition to ext4 as soon as XP get rotten. Thanks.

guanx · 03-12-2009, 05:30 AM

Quote:

Originally Posted by Stroker

Ext4 can have up to 2.5 minutes of delay before writing to disk, causing some potential problems if the system crashes.

Ubuntu Bug #317781

Where as Ext3 writes to disk every 5 seconds.

Don't worry. It's a parameter tunable via sysfs. It's not wise to be scared by the Ubuntu community, which is a collection of idiots. If you look at the ext4 wiki, you can find that Ubuntu is hostile to ext4.

GazL · 03-12-2009, 07:27 AM

Quote:

Originally Posted by guanx

Don't worry. It's a parameter tunable via sysfs. It's not wise to be scared by the Ubuntu community, which is a collection of idiots. If you look at the ext4 wiki, you can find that Ubuntu is hostile to ext4.

Except of course, you'll lose most of the performance advantages of running ext4 in the first place so it sort of defeats the purpose of using it.

Theodore Ts'o has posted two very informative posts on that bug report explaining what's going on and also how application developers really should be coding apps to prevent this sort of stuff.

317781/comments/45

317781/comments/54

Well worth reading, the second one especially so for any budding application writers out there.