# Nextcloud oc\_filecache growing huge : too many rows (hence backup fails with : lost connection to MySQL) **URL:** https://forum.yunohost.org/t/nextcloud-oc-filecache-growing-huge-too-many-rows-hence-backup-fails-with-lost-connection-to-mysql/16951 **Category:** Support apps **Tags:** nextcloud, english **Created:** [August 23, 2021, 8:31am UTC](https://forum.yunohost.org/t/nextcloud-oc-filecache-growing-huge-too-many-rows-hence-backup-fails-with-lost-connection-to-mysql/16951 "2021-08-23T08:31:14Z") **Posts on this page:** 1 **Showing post:** 5
### Author: ![wbk](https://forum.yunohost.org/letter_avatar_proxy/v4/letter/w/e0b2c6/32.png) [@wbk](https://forum.yunohost.org/u/wbk) #### Post date: [August 23, 2021, 4:22pm UTC](https://forum.yunohost.org/t/nextcloud-oc-filecache-growing-huge-too-many-rows-hence-backup-fails-with-lost-connection-to-mysql/16951/5 "2021-08-23T16:22:15Z")
> [@Lapineige](#): > > > [@wbk](#): > > > > Does the timeout match the actual runtime of the backup > > I don’t understand this. I mean, when you for example change the timeout from 120 seconds to 300 seconds, and compare the logs from the two attempts, does the second run about 180 seconds longer? Another guess: you changed the timeout of net\_r/w\_timeout, could it be that that timeout is not used by mysqldump? The flash layer of the SD card is heavily hammered and maybe has to clear blocks before writing data, MySQL is patient enough to wait, but mysqldump thinks MySQL has gone away? > [@Lapineige](#): > > Do you have a topic on this, so I can avoid the off-topic here ? Yes, [Nextcloud upgrade: how to shrink oc\_filecache.ibd (441GB at the moment)](https://forum.yunohost.org/t/nextcloud-upgrade-how-to-shrink-oc-filecache-ibd-441gb-at-the-moment/14285), but the topic is closed. If you have a suggestion, I will open a new topic for it. --- _[View the full topic](https://forum.yunohost.org/t/nextcloud-oc-filecache-growing-huge-too-many-rows-hence-backup-fails-with-lost-connection-to-mysql/16951)._