[Ocfs2-tools-devel] [RFC] mkfs adaptable cluster size depending on device size

[Sunil Mushran]

mkfs.ocfs2 has a concept of fstype which allows us to choose the
appropriate cluster size. The calculation takes the size of the volume
into consideration.

        -T filesystem-type
               Specify  how  the  filesystem  is  going to be used, so that
               mkfs.ocfs2 can chose optimal filesystem parameters for  that
               use. The supported filesystem types are:

                    mail   Appropriate for file systems that will host lots
                           of small files.

                    datafiles
                           Appropriate for file systems that  will  host  a
                           relatively small number of very large files.

                    vmstore
                           Appropriate for file systems that will host Vir-
                           tual machine images.

Sunil

On 07/23/2010 08:02 AM, Goldwyn Rodrigues wrote:
> Hi,
>
> Users tend to make filesystems without considering the clustersize for
> the filesystem depending on the device size. The result is that users
> make filesystems as large as 16TB with 4k cluster size and store huge
> files on such a filesystem. This generates a lot of metadata, and
> tools such as fsck take a lot of time. This increases exponentially
> with the size of the device.
>
> I suggest that we use an adaptable cluster size while creating a
> filesystem depending on the size of the device. Something in the lines
> GFS2 does with rgrps while creating a new filesystem. IOW, bigger
> the device size =>  bigger cluster size suggested. Of course, this will
> be over-ridden by the option provided at the command line.
> If you agree with the idea, please suggest a range for which a
> particular cluster size be used.
>
> Regards,
>
>