On 3/15/11 5:42 PM, David Shaw wrote:> Hello,
>
> I understand the need for a proper stride setting when formatting a
> filesystem on a RAID device. However, is there any problem in using
> a stride setting when formatting a filesystem on a regular non-RAID,
> non-SSD, just plain-vanilla-single-disk block device? I'm sure there
> isn't any benefit to it, but I'm curious if there is any harm.
>
> The reason I ask is I'm looking at some code here that can be used on
> either RAID or non-RAID devices. The stride setting it has is
> correct for the particular RAID setup it is intended for, but it also
> uses those settings when formatting a non-RAID device.
>
> David
just FWIW, recent kernels & e2fsprogs will just automatically pick
stride based on storage geometry - for md/lvm at least, and for
scsi devices that export this geometry as well.
ext4 has a little stripe-awareness in its allocator; otherwise, stride
just staggers bitmap starts so they don't all end up on the same spindle;
[1]
Offhand I don't think it'd cause any harm to set stride on non-raid.
-Eric
[1] ext2fs_allocate_group_table() in lib/ext2fs/alloc_tables.c