[CoolCold]

I definitely met several cases where support for shrinking would be beneficial - usually something about migrations and things like that, but yet I agree it's quite rare operation. Benefits come with lower amount of downtime window and/or expenses in time and duplicating systems.

I.e. back in ~ 2013-2014 while moving some baremetal Windows server into VMware, srhinking and then optimizing MFT helped to save AFAIR 2 hours of downtime window.

> except perhaps as a consequence of bad planning

Assuming people go to Clouds instead of physical servers because they may need to add 100 more nodes "suddenly" - selling point of Clouds is "avoid planning" - one may expect cases of need of shrinking are rising, now lowing. It may be mitigated by different approaches of course - i.e. often it's easier to resetup VM, but yet.

[adrian_b]

I do not see the connection between shrinking and migrations.

In migrations you normally copy the file system elsewhere, to the cloud or to different computers, you do not shrink it in place, which is what XFS cannot do. Unlike with Windows, copying Linux file systems, including XFS, during migrations to different hardware is trivial and fast. The same is true for multiplicating a file system to a big set of computers.

Shrinking in place is normally needed only when you share a physical device between 2 different operating systems, which use incompatible file systems, e.g. Windows and Linux, and you discover that you did not partition well the physical device and you want to shrink the partition allocated for one of the operating systems, in order to be able to expand the partition allocated for the other operating system.

Sharing physical devices between Windows and any other operating systems comes with a lot of risks and disadvantages, so I strongly recommend against it. I have stopped sharing Windows disks decades ago. Now, if I want to use the same computer in Windows and in another operating system, e.g. Linux or FreeBSD, I install Windows on the internal SSD, and, when desired, I boot Linux or FreeBSD from an external SSD. Thus the problem of reallocating a shared SSD/HDD by shrinking a partition never arises.

[CoolCold]

> Now, if I want to use the same computer in Windows and in another operating system, e.g. Linux or FreeBSD, I install Windows on the internal SSD

I'm not sure I've ever seen any server which had dualboot of this sort - meaning production systems, not tests/homelabs of course. Usually it's either Linux either Windows, and never FreeBSD (it's dead basically, over last 15 years at least).

That sounds more like desktop/laptop usage case, where experimenting can happen and planning is out of equation, cuz it's well, experimenting.

> I do not see the connection between shrinking and migrations.

You may think on "changes" as more wider term in addition to migrations - be it changing underlying drives under DB partition or need to free some space on in VG and LV to be able to use LVM snapshots (a looooooot of systems I see allocate all the space in VG at once and then cannot use snapshots because there is literally no space available) or some webhosting like cPanel/Plesk managed need more/less space for /var/{mail,you_name_it} and so on.

Again, there could be more reallife stories with XFS, but well it was not an option in many cases in the past. Nowdays, at least in my bubble, it's usually something clustered and you can do migration/changes on node-by-node basis and downtime window is avoided on another level, not by FS means.