I'm replacing a RAID array for a NAS.

I'm about to create a the ext4 partition on the primary, full-disk LV.

The original LV had been formatted ext4, with defaults,

mkfs.ext4 /dev/VG0/NAS03

I'm looking at the original drive's usage, hoping to optimize the new drive.

/bin/df /dev/VG0/NAS03 Filesystem 1K-blocks Used Available Use% Mounted on /dev/mapper/VG0-NAS03 1548182724 1383153132 86363468 95% /NAS03

/bin/df -i /dev/VG0/NAS03 Filesystem Inodes IUsed IFree IUse% Mounted on /dev/mapper/VG0-NAS03 98312192 1182797 97129395 2% /NAS03

For

1383153132 1K blocks = 1,416,348,807,168 bytes in use

results in an effective 'bytes-per-inode'

1,416,348,807,168 / 1182797 = 1,197,457 bytes/inode

The ext4 fs defaults for mke2fs on opensuse are

cat /etc/mke2fs.conf [defaults] base_features = sparse_super,filetype,resize_inode,dir_index,ext_attr default_mntopts = acl,user_xattr enable_periodic_fsck = 0 blocksize = 4096 inode_size = 256 inode_ratio = 16384

[fs_types] ... ext4 = { features = has_journal,extent,huge_file,flex_bg,uninit_bg,dir_nlink,extra_isize auto_64-bit_support = 1 inode_size = 256 } ...

The parameters are documented at

https://ext4.wiki.kernel.org/index.php/Frequently_Asked_Questions http://man7.org/linux/man-pages/man5/ext4.5.html

Assuming (correct?) that

"inode_ratio" == "bytes-per-inode"

Comparing the default vs effective ratios

16384 <<< 1,197,457

where the effective ratio for my current usage profile falls between

largefile = { inode_ratio = 1048576 blocksize = -1 }

& largefile4 = { inode_ratio = 4194304 blocksize = -1 }

Assuming that usage over time will be similar for the new LV, and

Usage: mkfs.ext4 [-c|-l filename] [-b block-size] [-C cluster-size] [-i bytes-per-inode] [-I inode-size] [-J journal-options] [-G flex-group-size] [-N number-of-inodes] [-m reserved-blocks-percentage] [-o creator-os] [-g blocks-per-group] [-L volume-label] [-M last-mounted-directory] [-O feature[,...]] [-r fs-revision] [-E extended-option[,...]] [-t fs-type] [-T usage-type ] [-U UUID] [-jnqvDFKSV] device [blocks-count]

for optimal performance, *should* the new LV fs be created as

mkfs.ext4 -T largefile ...

?

Might as well get it right before locking it in. So you are right, "-T largefile" may be OK for you. But seeing that your bytes-per-inode isn't *that* much over 1 MB, I'd be somewhat reluctant to do that. Number of inodes in the filesystem cannot be changed. So it is good idea to overprovision it just in case usage pattern of the filesystem changes somewhat. So in your case I'd go with inode ratio something like 131072 or 262144. Sure you'll have plenty of inodes free but it's better

On Sun 29-03-15 22:22:24, lyndat3@your-mail.com wrote: than having to recreate filesystem later when you find out you're running out of inodes. Honza

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