w1228 romb batt < 24h

You may end up with a singularity forming in your server closet if you don't replace it.

Just kidding.

What happens is the PERC controller will stop caching data and your disk performance may drop. That way if there's a power outage, it should prevent you from losing data (or minimize the chances of losing data.

It shouldn't cause any immediate issues if you have to wait a few days to get the new battery. You turn off the server, replace the battery as per the documentation, and power it back up. The server will run fine until you get it replaced.

The battery is degrading, though it isn't dead yet.

When it does die, the biggest impact is that the write-cache on your RAID card will be disabled. This will have potentially significant performance impacts, but will not affect stability. You have time to plan for a replacement-outage.

When the battery dies, it will just turn off the battery backed write cache. This could hurt performance a bit, but shouldn't be a huge deal to run like this in the short term.