ext4 Filesystem


Infinite Disk can take advantage of millions of older 32-bit devices that are being replaced with newer 64-bit devices worldwide by making use of the ext4 file system (instead of the default ZFS file system) in the Block Modules.

1. Reliability

Although the reliability of Block Modules are not important, it is still good to have a stable data store that reduces the need of activating Infinite Disk's self-healing feature.

To make ext4 more reliable, reduce reduce fsck time, reduce need for complete resilvering etc. but setting the following:

  1. set data=journal instead of data=ordered
  2. enable metadata checksums (-O metadata_checksum,metadata_checksum_seed to mkfs.ext4)
  3. enable journal_checksum
  4. disable delayed allocation (nodelalloc)
  5. enable "extent" feature (to defrag online and to reduce fsck)
  6. mount with auto_da_alloc
  7. enable errors=remount-ro so ext4 will become read only when metadata corruption

2. Maintenance

Most need "root permission" to run:

  1. Defragmentation - e4defrag command
  2. Trim - fstrim command

3. Logical Volume Manager

Use of Logical Volume Manager (LVM) to create snapshots and backups of ext4 in the Block Modules is possible, but is NOT normally needed.