Re: 64bit ext4 and kernel version compatibility
On Thu, Jan 09, 2020 at 05:06:29PM +0000, Tixy wrote:
> On Thu, 2020-01-09 at 14:35 +0300, Reco wrote:
> > On Wed, Jan 08, 2020 at 06:08:16PM -0600, R. Ramesh wrote:
> > > Before I get the source and build and update e2fsprogs and then the
> > > file system, I want to make sure that my current kernel version does
> > > not have any limitation to support 64bit ext4.
> >
> > You kernel should support the feature, as it was introduced back at the
> > version 3.6 of the kernel - [1].
> >
> > [1] https://ext4.wiki.kernel.org/index.php/Ext4_Metadata_Checksums
>
> That web page is talking about metadata checksums I can't see anything
> about '64-bit'.
Let me read it for you (note kernel version):
Install Linux 3.6+ and e2fsprogs 1.43-WIP.
modprobe crc32c-intel
mkfs.ext4 -O metadata_csum,64bit /dev/path/to/disk
To enable "metadata_csum" in its full glory one needs to enable "64bit"
fs feature:
In a perfect world, one could simply enable metadata checksums ...
Therefore, it is best to start by formatting a fresh
filesystem with 64-bit support enabled ...
>What I'm assuming the OP is interested is 64-bit block numbers because
>they said they want to "convert ext4 fs on this server to 64bit so that
>I can grow it past 16TB limit". Note from me, 4kB sized blocks * 2^32 =
>16TB, so block numbers whould need to be more than 32-bit for bigger
>drives.
Same page says:
Therefore, it is best to start by formatting a fresh filesystem with
64-bit support enabled, since it is not possible to upgrade a 32-bit
filesystem to a 64-bit filesystem.
So if "convert" = "mkfs", then OP is fully set.
But then again, it's nothing that can't be solved by pre-existing
backup.
Reco
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