I upgraded from F25 to F26 yesterday and ever since have been seeing the system frequently become totally unresponsive.

It seems to be quite random and can only be resolved by hitting the reset button to reboot.

On other occasions it doesn't quite die but starting anything takes several minutes rather than seconds.

Thunderbird and dnf are examples but sometimes there is just no response to key strokes or clicks.

The only clue that I have seen is that top often shows very high wait I/O levels and swap space is sometimes (but not always) low.

Nothing has changed in the system workload or configuration.

This is a production machine so any help will be very welcome.

Cheers and thanks,
Stephen

I've been noticing the same thing. Watch it! That could be a sign of imminent HDD failure. I've had a professional installer tell me that very thing.

If you've been following my Data Migration thread, you'll find in there a solution Fred Roller suggested. That is: you have two drives (HDD or SSD, it doesn't matter which except for power and space requirements), one small (120 GB minimum size) and one large (as large as you want). You install Fedora on the smaller drive. Then you format the larger drive in the same filesystem (I use ext4) and mount it in your Linux directory tree under a name of your choosing. (Fred uses /crypt, but any name will do--but if you decide to use /cache, make sure that's not a reserved word.) Then for each user account:

1. Create new directories for every user. Thus for every folder named /home/username (where /username/ is the name on a user account), create, say, /crypt/username.

2. Use chown and chmod (as a "sudoer") to set ownership, group membership, and permissions exactly as they are in the original.

3. Create the next level of subfolders of every user folder, and again use chown and chmod to set their ownerships, group memberships, and permissions exactly as you would have them.

4. Now, in each /home/username directory, /remove all subdirectories/. And each time you do that, create a /symbolic link/ to the counterpart directory on the larger drive. For example:

$ sudo rmdir Documents

$ sudo ln -s /crypt/username/Documents /home/username/Documents

If I understand this properly, now those new folders will become visible in /home/username as if they actually resided there. But they will have far more capacity and will be safe.

5. Do this also for any hidden configuration folder, such as for Thunderbird or Kmail, that you want to preserve from one installation to the next.

From then on, you can do clean installs of each successive iteration of Fedora, re-create your users and groups, remove all top-level folders from each user account, and re-create the symlink structure. You can even swap out the smaller HDD or SSD without fear of compromising your data on the larger drive.

An SSD makes an inherently better system drive than an HDD. File access is much faster. Furthermore the system drive, being the workhorse, has a heavier work burden. An SSD will take a lot more punishment than an HDD can take, and for far longer. In fact, a system drive is likely to fail first, for this reason. So using an SSD is far preferable. I got mine for less than $60 US, tax included.

Just remember to power up your system at least once every three months (no more than four) to make sure the SSD doesn't "forget" everything you "taught" it. I use my desktop every day, or idle it for no more than two weeks at a time, so that doesn't present a problem.

I happen to be planning to use an SSD for the user-data drive as well. I have it on hand from an earlier plan (now abandoned) and might as well use it. You might do the same, if you are doing things like torrenting or frequent uploading or downloading or running a database or Web site or anything else that causes you to access user-data files nearly as often as you access system files.

Temlakos