Pin read hits percentage extremely low constantly
A short blog more or less asking for some insight, insight as I fail to understand why this would occur like this. Pin Read hits is one of the number of measurements that you can use to determine how the cache manager is doing on w Windows machine. I’m monitoring an environment for a while now and the servers in that environment seem to have an issue but I can’t get my hands around it.
The server is a Windows machine with 4GB of memory, it’s an old machine but still running and doing it’s job for the customer. There are no specific application running there. I’m monitoring the server remotely and therefor got limited view on it. There is one more server having the same issue, going by it’s name i would call it a backup server. Both servers are virtual server running on a Hyper-v host.
The issue, if it is an issue, is that the Pin read hits percentage is too low, from what I gather from this metric it should be around 100% all the time.
In this environment on two of three servers I monitort the value is constant around 13% which is a big difference to 100% if you ask me.
If you look for documentation on this metric the Internet suddenly is a small place. I found several documents but all just have the same information like a copy of the original Windows 2000 document I found at Microsoft.
What is pinning?
so what I understand of it, correct me if I’m wrong, pinning is keeping data in cache because Windows, the system, is not done with it yet and needs access fast. Data from cache is faster accessible than data from disk. When unpinning happens the data is written to disk. Perhaps this is a too simple explanation of pinning but I think that is what it is.
So what does that mean, with a high (100% ) pin read hit percentage a lot of pinning is happening. So that means a large number of files are being pinned and therefore either the cache is large or things change fast… still on the right track?
So if the number is low, does that mean nothing is happening on that server.. is the number not that bad and is the server just at rest. Because I don’t know why it could be this low I looked at the page file, the page file is not used at all…
So I checked the memory usage to see if there was somehow a shortage anywhere. The server is only equipped with 4GB of memory and 45% of memory is utilized so that can’t be the issue.
I also looked at the disk and also there I found nothing out of the ordinary. So I’m on a dead track. don’t know where to look next. I know articles shouldn’t end in questions but I break that rule now… I need your help to solve this. so any ideas please let me know.. and I dive into them.