New Use Cache option

[itimpi]

We seem to be getting an increasing number of cases where users have set Use Cache to No, but files for a share end up there anyway due to the way Linux handles move as a rename or the way a docker container is configured.    A new setting option for Use Cache might help avoid this.   The behavior would be similar to the current “No” setting for new files, but when mover runs it WOULD move any files it finds belonging to the share from cache to array.

 

i could not think of a short name for this mode    The best I could come up with is “clear” but maybe someone will have a better idea?    The other way would be to make the “no” setting work in this way as it is what most users seem to think “No” means, and rename the current “No” behaviour to something like “Keep” to indicate any files already on cache are kept there.   Any thoughts?

[JonathanM]

8 hours ago, itimpi said:

The other way would be to make the “no” setting work in this way as it is what most users seem to think “No” means, and rename the current “No” behaviour to something like “Keep” to indicate any files already on cache are kept there.   Any thoughts?

Given your options, I prefer renaming the current "No" to something else, and the new "No" move from cache to array just like yes does.

 

What I really think needs to happen is a total redesign of the cache pool settings.

 

Divorce the two concepts of file placement and mover action, like this.

 

Each user share can define both initial and final file location.

 

New files destination (array, cache pool 1, cache pool 2, etc)

Mover destination (leave in place, array, cache pool 1, cache pool 2, etc)

 

That way when somebody updates a share allocation and runs the mover, it's obvious what should happen.

 

Bonus points for conditional mover behaviour based on age or space thresholds.

Extra special bonus points for second conditional destination, i.e. move files to cache pool 2, move files already in cache pool 2 older than 1 week to array.

[itimpi]

I was trying to suggest a change that would be simple to implement, require virtually no GUI changes, but still address the commonest mistakes that users make with the use Cache setting.   That might make it easy to get it into a release in the near future, possibly even the 6.9 release.   I do think on that basis that the “No” option should get the new behavior and the current behavior of “No” where mover does nothing for user share files on the cache (which is rather a special Use Case anyway) should get a new name.

 

The redesign that you talk about sounds like something that would be much bigger change and although possibly desirable not likely to make any release in the near future I would think.   I could be proved wrong though  

[trurl]

9 hours ago, itimpi said:

i could not think of a short name for this mode

I can't think of any single word that adequately promotes any real understanding of any of the existing modes. Yes and No were mostly OK when they were the only options, but Prefer and Only made even Yes and No confusing.

 

1 hour ago, jonathanm said:

Divorce the two concepts of file placement and mover action

That might make things clearer. Something is going to have to be reworked to support multiple cache pools. Then we will all have to learn new ways of talking about all this, and lots of old posts on the forum will contain obsolete advice.

[-Daedalus]

In my mind, this is what the existing "No" setting should do, evidenced by the amount of people expecting it to do this, and then being surprised that files are still on the cache.

 

So, seems like as long as there was a notification somewhere, you could just change the behaviour of the existing setting, and leave it at that.

I can't really envision a use-case where you would want an array only share, but have certain files always on the cache, unaffected by the mover. If there is one, let me know.

[JonathanM]

24 minutes ago, -Daedalus said:

I can't really envision a use-case where you would want an array only share, but have certain files always on the cache, unaffected by the mover. If there is one, let me know.

I use this option for my domains share. I like to experiment with VM's, but don't want them all on my cache, only the ones I keep running regularly. When I fire up a new VM, it defaults to the array, which has virtually unlimited space at the cost of speed. If I want to, I can leave it there, or manually move the disk image to the cache, or from the cache to the array, if I replace one of my regular VM's with a newly spun up version but want to keep the old one around.

 

I never want mover to mess with my VM files, and I don't enjoy editing XML files just to point to a new location when I move between cache and array. I don't want newly created VM's to take up space and IO on my cache disk and possibly disrupt my always on VM's for pfsense, home automation, theater room, etc.

 

[Squid]

Along the same lines:

 

 

[-Daedalus]

8 hours ago, jonathanm said:

I use this option for my domains share. I like to experiment with VM's, but don't want them all on my cache, only the ones I keep running regularly. When I fire up a new VM, it defaults to the array, which has virtually unlimited space at the cost of speed. If I want to, I can leave it there, or manually move the disk image to the cache, or from the cache to the array, if I replace one of my regular VM's with a newly spun up version but want to keep the old one around.

 

I never want mover to mess with my VM files, and I don't enjoy editing XML files just to point to a new location when I move between cache and array. I don't want newly created VM's to take up space and IO on my cache disk and possibly disrupt my always on VM's for pfsense, home automation, theater room, etc.

 

 

 

6 hours ago, Squid said:

Along the same lines:

 

Fair points both. Different ways to do each that doesn't require the current implementation, but options are always good.