Updating snappymail on a nextcloud instance with occ command is extremely slow!

[akhil1508]

Describe the bug

• I have an instance with ~10k+ active users on it
• Whenever I have to do occ app:update snappymail, there is a downtime of at least 20 minutes (sometimes much more, up to 3h)
• My cache is set to apcu
  • Earlier cache was set to use files so it was doing an rmdir on all the files when the app was updating; it used to take upwards of an hour to update snappymail then
• Would be great if we could reduce this to a few minutes/seconds as the app update is just about loading new files/classes and not much else
• Its a lot of deletion of folders like unlink appdata_snappymail/_data_/_default_/cache/__/ab/cd/{username_domain}/ef/gh/abcdefghigk
  • I use cephfs for storage where deletes are notoriously slow operations
  • Deleting 1000s of files takes very very long

To Reproduce Steps to reproduce the behavior:

On a big nextcloud instance

1. occ app:disable snappymail
2. occ app:update snappymail
3. occ app:enable snappymail

Expected behavior

• Fast upgrade process of snappymail with nextcloud

[akhil1508]

@the-djmaze If you can give some pointers/guidance, would be happy to develop to fix this

[the-djmaze]

I don't know how space your cache is using. But maybe use memcache?

And disable cache could also be an option if imap is fast.

A periodic rm -dfr /cache might be faster.

[akhil1508]

@the-djmaze

I don't know how space your cache is using.

It's not a lot of space but it's a lot of folders.. and rm is a slow operation on cephfs with thousands of folders with many subfolders each

But maybe use memcache?

This is what I don't understand. I already use APCU as the cache, why is the app still using files to cache?

[the-djmaze]

When creating the \MailSo\Cache\DriverInterface fails, it will use the File driver. That's why you have a lot of cache files.

You must check your cache driver settings.

[akhil1508]

You must check your cache driver settings.

@the-djmaze I am checking this.

In the meantime until I can debug it could you tell me if it is safe to do:

1. occ app:disable snappymail
2. mv cache some-other-location/cache
3. occ app:update snappymail
4. occ app:enable snappymail

I've actually had to do the mv step in during update before as it was extremely slow and users were complaining about downtime.

[the-djmaze]

Yes, that is safe enough.