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0.06% cache hit rate...

Posted: Mon May 23, 2022 8:00 pm
by bzamora
Hi, I wanted to ask for some help understanding why my cache hit rate is so low, and what should I change to improve it.

Key facts:
- Windows Storage Spaces 6TB, with L2 SS2 ~500GB, L1 RAM ~6GB
- Defer-write enabled

In steady state 0.06% cache hit rate.

This is a server for my storage, it is fairly unused, so in steady state, almost no operations.

I've attached the screenshot, and a 2nd screenshot 20 minutes later, also showing the config

Thanks!
Bernardo

Re: 0.06% cache hit rate...

Posted: Wed May 25, 2022 4:01 am
by Support
Cache hit rate is for read performance. From the statistics panel, I see that Total Read is about 15GB, and "L2Storage Write" is about 15GB. This means that L2 cache is populating data. It is normal that cache hit rate is low when data was first read. You may need to run the server for several days and then check the hit rate.

PS. because you use both L1 and L2 for defer-write, you can check the option "Flush L1 Cache to L2 Cache" in the Advanced Defer-Write Options dialog.

For more information about L2 cache and defer-write, please see
https://www.romexsoftware.com/en-us/pri ... cache.html
https://www.romexsoftware.com/en-us/pri ... write.html

Re: 0.06% cache hit rate...

Posted: Thu Jun 09, 2022 12:23 am
by bzamora
I rebooted the PC and the cache started working!