Magento site is frequently getting CACHE issue and failing to serve CSS, site is getting broken page

Question

Magento site is frequently getting CACHE issue and failing to serve CSS, site is getting broken page.

Once after flush redis cache or restart of redis is bringing site into normal position.

Below cache technologies being integrated for magento web site.

1. Magento: 1.9.1.0
2. Redis: 3.0.5
3. Lesti FPC

Server have two redis instance running with Port No: 6379 and 6380

Site is configured with redis cache for magento backend and full page cache (FPC site cache), Redis's 6379 instance is configured for both cache setup but redis database are different.

Configurations as below:

backend redis configurations in local.xml

[![<cache>
<backend>Cm_Cache_Backend_Redis</backend>
 <backend_options>
 <server>127.0.0.1</server>
 <port>6380</port>
 <persistent>cache-fpc</persistent>
 <database>1</database>
 <password></password>
 <force_standalone>1</force_standalone>
 <connect_retries>1</connect_retries>
 <lifetimelimit>86400</lifetimelimit>
 <read_timeout>10</read_timeout>
 <compress_data>1</compress_data>
 <compress_tags>1</compress_tags>
 <compress_data>gzip</compress_data>
 </backend_options>
</cache>][1]][1]

FPC site cache redis configurations in fpc.

 <fpc>
 <lifetime>86400</lifetime>
<backend>Cm_Cache_Backend_Redis</backend>
 <backend_options>
 <server>127.0.0.1</server>
 <port>6380</port>
 <persistent>cache-fpc</persistent>
 <database>1</database>
 <password></password>
 <force_standalone>1</force_standalone>
 <connect_retries>1</connect_retries>
 <lifetimelimit>86400</lifetimelimit>
 <read_timeout>10</read_timeout>
 <compress_data>1</compress_data>
 <compress_tags>1</compress_tags>
 <compress_data>gzip</compress_data>
 </backend_options>
</fpc>

Scheduled redis cache clearing cronjob as per this reference URL: http://inchoo.net/magento/using-redis-cache-backend-and-session-storage-in-magento/

Ref Image of broken site home page :

• MauroNigrele: Are you using any tool to monitor redis status/amount of memory used? give a try to: github.com/steverobbins/redis-status but if you want to get alerts or better stats try installing new rellic, appdinamics or another monitoring tool.
• ladle3000: Have you ever found the solution? I'm facing the exact same and going nuts here.
• Allysin: @ladle3000 Has anyone ever found a solution to this? I'm having the same problem on Magento 2.4.2-p1
• ladle3000: @Allysin I left for bigcommerce years ago

Answer 1

For us this came down to being default Magento configuration cache.

Simply disabling the first cache (configuration cache) in backend is a quick fix/workaround.

We fixed with the following https://github.com/AmpersandHQ/magento-ce-ee-config-corruption-bug

• ladle3000: Also we are using Magento 1.9.1 which is what the OP was using too. I think it might be a bug in this specific version.
• Scruffy Paws: The related patch SUPEE-4755 worked like a champ for us on Magento 1.9.2.4

Answer 2

Did you have CSS styles merged? Possibly, unmerging CSS files should fix the issue (System-Confguration-Advanced-Developer-CSS Setting-Merge CSS files).

However, you will need HTTP/2 on the server side, use compact version of styles, or even setup static compression to keep the same performance.

Answer 3

Also to avoid this issue I scheduled below cronjobs, which is flushing Redis cache

Redis Cache clean up script

30 02 * * * /usr/local/bin/redis-cli -h localhost -p 6379 flushall
31 02 * * * /usr/local/bin/redis-cli -h localhost -p 6380 flushall

Still some point of time I am hitting with the issue.

• ladle3000: This is like taking painkillers for a headache from a brain tumor. Masks it for a couple hours.