Subscribe

CP type D

Hi,

There isn't really performance issue, but 90% of CPs are D.
How should I deal with it? I haven't seen it before, so thats why it got my attention.
I "know" what it is, and thats why it sounds bit crazy.
FAS3240HA has 8Gb RAM (how much from that is for writes, I don't know) but we don't receive CP type F at all.
So, NVMEM is 1Gb in this system, 500Mb from it is for partner, and rest "500Mb " is divided to two banks.

It means Storage is running out of memory (for writes) before there is 250Mb data in NVMEM?


Br.
Ismo.

Re: CP type D

The 8GB RAM are for read cache (and a little bit for writes). When WAFL writes something it is always stored in RAM, because it is very likely to being read very soon. Then depending on the age and space it is being purged sometime later.

NVMEM is not a write cache.

*It means Storage is running out of memory (for writes) before there is 250Mb data in NVMEM?*

Is this question related to the D type CP? Or is it a general WAFL / NVMEM question?

Re: CP type D

Hi,

Thanks for replying.

I know, NVMEM isn't write cache, but data is written there from RAM, And it feels weird that I'm seeing D instead F.
Is it possible to get CP type F at all in here, if RAM is running out before NVMEM 256Mb? Or is there "shared" space in RAM, so could it be that read operations are controlling whole RAM, and there is no space for new writes?

My understanding is that RAM is running out of free space (for writes) when CP type D occurs. Basically every write request goes from RAM to NVMEM, but CP is triggered by D, it means there isn't 256Mb writes in memory. Because CP type F hasn't occur.

Br.
Ismo.