Avian’s Blog

Just a quick note, because I found this confusing today. stride and stripe_width are extended options for ext filesystems that can be used to tune their performance on RAID devices. Many sources on the Internet claim that the values for these settings on existing filesystems can be read out using tune2fs or dumpe2fs.

However it is possible that the output of these commands will simply contain no information that looks related to RAID settings. For example:

$ tune2fs -l /dev/... | grep -i 'raid\|stripe\|stride'
$ dumpe2fs -h /dev/... | grep -i 'raid\|stripe\|stride'
dumpe2fs 1.44.5 (15-Dec-2018)

It turns out that the absence of any lines relating to RAID means that these extended options are simply not defined for the filesystem in question. It means that the filesystem is not tuned to any specific RAID layout and was probably created without the -E stripe=...,stripe_width=... option to mke2fs.

However I've also seen some filesystems that were created without this option still display a default value of 1. I'm guessing this depends on the version of mke2fs that was used to create the filesystem:

$ dumpe2fs -h /dev/... |grep -i 'raid\|stripe\|stride'
dumpe2fs 1.44.5 (15-Dec-2018)
RAID stride:              1

For comparison, here is how the output looks like when these settings have actually been defined:

$ dumpe2fs -h /dev/md/orion\:home |grep -i 'raid\|stripe\|stride'
dumpe2fs 1.44.5 (15-Dec-2018)
RAID stride:              16
RAID stripe width:        32