Re: WD Passport 2T hard drive formating question.
Le Monday 10 November 2014 19:32:39, Juan R. de Silva a écrit :
> > $ man mkfs.ext4
> >
> > Look for "-m" argument.
>
> "-m" option default value is 5% (!) = 50 GB space. No minimal reserved
> space is specified/recommended in man pages.
>
> GParted allocated to file system 1.616% = 29.42GB (quite generous against
> default 5%).
>
> For NTFS, on the other hand, only 0.0067% were allocated = 122.66 MB.
>
> I do understand that some space must be reserved for the super-user to
> allow avoiding fragmentation + journal, etc. However the amount of space
> reserved seems to me unreasonably high - 29 GB vs. 123 MB.
>
> Yes, I can tinker the situation to some extent with other mkfs.ext4
> options. But I do not know if the gain is worth of efforts.
>
> Besides, since the drive will be used for backup, I do not want to
> sacrifice the stability of the file system in order to preserve space
> either.
>
> So, the question is, to which extent and with what result can I tinker
> with mkfs.ext4 options.
You seem to have overlooked Darac Marjal's response.
29GB is not the space reserved for the super user. It is made of blocks set
aside for inodes storage and super blocks replication (see option -T in
mkfs.ext4 man page).
I have been using xfs on external USB HDD because I never succeeded in the
right value between too many inodes and not enough.
And the space reserved for the super user is really a space that can only be
written by root. It is not a space required to operate the disk. It is made of
blocks reserved to prevent a user from filling up the disk and prevent anybody
(including root) from logging in. As far as I understand, you don't need it on
an external storage. You can set -m0 when formatting the disk.
Frédéric
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