Help explaining write cache

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ZOX
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Help explaining write cache

Post by ZOX »

Hello!

I'm testing Primocache on our local file server.

It has a 100GB L2 storage on a SSD and is used for caching mirrored volume of two 1TB HDDs (mirroring is done via Windows).
All clients are connected over network.

I've noticed that if any write cache is configured (e.g. anything else but 100% read cache), newly created files are not visible to other computers on network, just on a machine that created it.
Deferred write is disabled.
As said, without any write cache, files are immediately visible to all.

Is that normal behavior or am I doing something wrong?

Thank you!
RobF99
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Re: Help explaining write cache

Post by RobF99 »

My guess is that it is related to your network settings on the server and clients. If you go here https://docs.microsoft.com/en-us/window ... le-server/ there are a lot of registry tweaks. My intuition says that one of the CacheLifetime entries will correct your problem.

Also, do a search for this document: perf-tun-srv-r2.docx. It is an official Microsoft document for tuning many aspects of your network. The tweaks had a clearly perceivable impact on our small office network's performance. We use Primocache on a small server with write caching and have never experienced the problem you are describing.
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Support
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Re: Help explaining write cache

Post by Support »

ZOX wrote: Wed Jul 07, 2021 12:27 pm Deferred write is disabled.
The issue seems quite weird...Since Defer-Write is disabled, it is almost impossible to affect normal process. We hadn't seen such issues before. I'm sorry that currently we have no idea about this. But for L2 cache, it is not recommended to enable write cache if you are not using it for defer-writing.
InquiringMind
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Re: Help explaining write cache

Post by InquiringMind »

ZOX wrote: Wed Jul 07, 2021 12:27 pm ...if any write cache is configured (e.g. anything else but 100% read cache), newly created files are not visible to other computers on network, just on a machine that created it...
If an existing file is changed (with write caching enabled), are the changes then visible from other computers on your network?

If no, then this suggests a problem with cached writes being deferred when they should not be.

If yes (so only newly created files are affected) then this suggests that directory data is not being updated for remote connections, which may indicate a Browse Master issue.
ZOX
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Re: Help explaining write cache

Post by ZOX »

Thanks everybody for suggestions, I'll try to find the root cause and will report back.
thitluoc
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Re: Help explaining write cache

Post by thitluoc »

Did you find the root cause? Thank you
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