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loewc
01-May-2018, 09:05
Hi,

this is more a general question ... about a point that drives me crazy

these days its quite easy to extend a disk (vmware, whaever) - And it really complicated to extend the filesystem.

This is perhaps a question to SUSE itself:
why it is required to partition the disk? why the installer requires that? grub2 can boot from ext4,btrfs,...

the problem is that resizing a partition never(?) works without a reboot
For additional disks you can use lvm or mkfs on the whole disk ... but not with Yast. Why?

I dont want to say that, but under windows this is simple ... extend (vmware)disk -> disk-manager -> extend ... thats all
or ZFS ...


What do you think?


Perhaps it is possible to address this in future versions ...


Chris

ab
01-May-2018, 17:26
On 05/01/2018 02:14 AM, loewc wrote:
>
> these days its quite easy to extend a disk (vmware, whaever) - And it
> really complicated to extend the filesystem.
>
> This is perhaps a question to SUSE itself:
> why it is required to partition the disk? why the installer requires
> that? grub2 can boot from ext4,btrfs,...

My understanding is that embedding the bootloader in an unpartitioned disk
does not work. For non-boot disks, though, like those data disks that
everybody adds, everything is probably fine technically because there is
no booting from those, so no bootloader needing to be embedded.

> the problem is that resizing a partition never(?) works without a
> reboot
> For additional disks you can use lvm or mkfs on the whole disk ... but
> not with Yast. Why?

See above; I think mostly Yast does not differentiate between the known
problem of a disk with a boot loader, and the known-to-work situation of
extra disks. Yast is mostly about user setup, and probably used 90% of
the time for disk/storage things when setting up a new system, so boot
disks are its primary focus. With that said, I know there is an
enhancement request in to change this and related support statements.

> What do you think?
>
> Perhaps it is possible to address this in future versions ...

I think your best bet to ensure that, particularly as SLE 15 is currently
approaching release, is to make sure official routes (vs. unofficial
routes like this forum) are also pursued; account/sales representatives
are good people to talk to about this. FATE 324990 is for this issue
specifically, I believe, though I have only heard that from others.

--
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KBOYLE
01-May-2018, 17:37
loewc wrote:

>
> Hi,
>
> this is more a general question ... about a point that drives me crazy
>
> these days its quite easy to extend a disk (vmware, whaever) - And it
> really complicated to extend the filesystem.

That is not exactly true. A physical disk can't be extended! ;-)

Yes, it is relatively easy to extend a virtual disk because, in
reality, that virtual disk is often just a file and increasing the size
of the file increases the size of the disk making additional free space
available on the disk.


> This is perhaps a question to SUSE itself:
> why it is required to partition the disk? why the installer requires
> that? grub2 can boot from ext4,btrfs,...

The answer to your question about partitions has already been explained
here:
https://en.wikipedia.org/wiki/Disk_partitioning


> the problem is that resizing a partition never(?) works without a
> reboot

Before a partition can be used, it has to be formated... for a specific
filesystem. For performance reasons, many operating systems keep copies
of data in memory including frequently accessed parts of the filesystem
itself. If you were to change parts of the filesystem on the disk and
the system were to rewrite the data it has cached in memory, the disk
would become corrupted. For this reason, changes to most filesystems
cannot be done while the disk is being used.

> For additional disks you can use lvm or mkfs on the whole disk ... but
> not with Yast. Why?\

It depends what you are trying to do. YaST Partitioner works. You can
increase the size of a partition or an LV very easily.

> I dont want to say that, but under windows this is simple ... extend
> (vmware)disk -> disk-manager -> extend ... thats all
> or ZFS ...

The first step is easy. You are adding free space to the virtual disk
but that doesn't increase the size of any partitions.

> What do you think?

It is relatively easy to increase the capacity of a virtual disk. Since
disks use a standard partitioning scheme, many generic tools will allow
you to increase the size of a partition as long as there is free space
on the disk and there isn't another partition adjacent to it. With LVM,
space from multiple disks can be used to create or increase the size of
a logical volume.

A filesystem is installed into a partition or a logical volume. To
increase the capacity of the filesystem, you need free space in the
partition or the LV. Since each filesystem is different you need to use
different tools for different filesystems. The changes you can make
depend on the specific filesystem. Most (I hesitate to say all) Linux
filesystems can be expanded easily with tools included with the OS but
not while the filesystem is mounted and in use.

The ability to expand the C: drive on a Windows server while it is
being used is a nice feature but it only works on a Windows server, not
a Windows Workstation. There are other "features" of a Windows
filesystem that aren't so nice so it's up to you to select a filesystem
(and OS) that provides the features you need.


> Perhaps it is possible to address this in future versions ...

> Chris

Perhaps...

--
Kevin Boyle - Knowledge Partner
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