Wow, it takes a really long time to make a 2TB ext2fs. Are there
better-than-default options that could be used for a large filesystem?
mke2fs 1.34 (25-Jul-2003)
Filesystem labelOS type: Linux
Block size=4096 (log=2)
Fragment size=4096 (log=2)
244203520 inodes, 488382016 blocks
24419100 blocks (5.00%) reserved for the super user
First data block=0
14905 block groups
32768 blocks per group, 32768 fragments per group
16384 inodes per group
Superblock backups stored on blocks:
32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208,
4096000, 7962624, 11239424, 20480000, 23887872, 71663616, 78675968,
102400000, 214990848
-jwb
On Feb 07, 2005 09:58 -0800, Jeffrey W. Baker wrote:> Wow, it takes a really long time to make a 2TB ext2fs. Are there > better-than-default options that could be used for a large filesystem? > > mke2fs 1.34 (25-Jul-2003) > Filesystem label> OS type: Linux > Block size=4096 (log=2) > Fragment size=4096 (log=2) > 244203520 inodes, 488382016 blocks > 24419100 blocks (5.00%) reserved for the super user > First data block=0 > 14905 block groups > 32768 blocks per group, 32768 fragments per group > 16384 inodes per group > Superblock backups stored on blocks: > 32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208, > 4096000, 7962624, 11239424, 20480000, 23887872, 71663616, 78675968, > 102400000, 214990848Yes, if you are creating larger files. By default e2fsck assumes the average file size is 8kB and allocates a corresponding number of inodes there. If, for example, you are storing lots of larger files there (digital photos, MP3s, etc) that are in the MB range you can use "-t largefile" or "-t largefile4" to specify an average file size of 1MB or 4MB respectively. You can also use -i or -N (see man page) to override the default bytes-per-inode value. This will also speed up e2fsck noticably. Cheers, Andreas -- Andreas Dilger http://sourceforge.net/projects/ext2resize/ http://members.shaw.ca/adilger/ http://members.shaw.ca/golinux/ -------------- next part -------------- A non-text attachment was scrubbed... Name: not available Type: application/pgp-signature Size: 189 bytes Desc: not available URL: <http://listman.redhat.com/archives/ext3-users/attachments/20050208/7fe2e38c/attachment.sig>
Ted, Could you explain why filesystem performance will degrade when the last 5% is used? I have several 1TB filesystems w/ only 1% reserved. The man page describes this space as "reserved for the super-user". I always assumed this was a buffer for root to be able to perform operations on a full filesystem. It seems as though 10GB is more than enough. Is this not the case? Thanks. - Jeff -----Original Message----- From: ext3-users-bounces at redhat.com [mailto:ext3-users-bounces at redhat.com] On Behalf Of Theodore Ts'o Sent: Tuesday, February 08, 2005 9:03 PM To: kwijibo at zianet.com; ext3 users list Subject: Re: mke2fs options for very large filesystems On Tue, Feb 08, 2005 at 12:59:53PM -0700, Andreas Dilger wrote:> On Feb 08, 2005 08:00 -0700, kwijibo at zianet.com wrote: > > Just as a side note but do you really want to reserve 5% > > of your 2TB partition for root?The filesystem performance will degrade if you eat into the last 5%, but as long as you're willing to live with this tradeoff, and assuming you don't need to reserve space for things like log files, then sure, you can always drop the percentage.> > Another side question on this. Is it possible to make mkfs > > accept non-integer values for the reserved percentage? > > It is getting to the point these days where partitions > > are getting so big that even 1% is becoming quite a waste. > > However it would still be good to have some space reserved. > > The value is stored in the kernel as a blocks count, so it is possible > to store any value there. It should be possible to change the mke2fs > and tune2fs option parsing to accept a float there. I think you can > set this manually via debugfs and "ssv" (in the latest e2fsprogs there > is also a command to set a single superblock value).The officially supported to set a specific number of reserved blocks is tune2fs -r <number_of_reserved_blocks> <filesystem-device-file> Since mke2fs sometimes is used in install floppies, etc., I decided there was no point to drag in floating point routines, especially when you can always set the number of reserved blocks directly using tune2fs -r after you create the filesystem. - Ted _______________________________________________ Ext3-users mailing list Ext3-users at redhat.com https://www.redhat.com/mailman/listinfo/ext3-users