More detailed information on flushing write cache data

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Axel Mertes
Posts: 157
Joined: Thu Feb 03, 2011 3:22 pm

More detailed information on flushing write cache data

Post by Axel Mertes »

I have currently one server with 2 TByte read/write cache and one server with 480 GB Optane read/write cache.

When ending the software or flushing the cache, I can only see a running bar with no start/end, so it's hard to tell how long it will take. And believe me - it takes a serious amount of time. We are talking about 1/4 TByte or more typically.

Given that you know exactly how many blocks you need to flush to disk, couldn't you add a more detailed display such as:

m of n total blocks written
m*blocksize/x seconds [B/s, KB/s, MB/s, GB/s] written
x seconds taken, y seconds to go (prediction)
a true progress bar in %

That would be very welcome and - by the way - feel much safer when you really see it writing all data through to the end.

Cheers
Axel

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support
Posts: 2702
Joined: Sun Dec 21, 2008 2:42 am

Re: More detailed information on flushing write cache data

Post by support »

Thank you for the suggestion!
We did consider this before. However, it is not as easy as we thought. The flush is not a simple process, thinking that new write-data might come while flushing.
But anyhow, we will reconsider this feature your requested and try to support it.
Primo Ramdisk | PrimoCache
Romex Software Support

Axel Mertes
Posts: 157
Joined: Thu Feb 03, 2011 3:22 pm

Re: More detailed information on flushing write cache data

Post by Axel Mertes »

OK, I understand. But then all that could happen is that the amout of total blocks is increasing again, right, potentially setting back the progress bar. I could live with that...

But when I think about it: Wouldn't that mean that a flush to disk may end up running forever, if enough new disk data is coming in?
I have not seen that at all...

We are not talking about the typical flush to disk operation that is done on timer, but the flush to disk operation that is manually executed or executed because of stopping the cache service or shutting down the system. I would expect these manually starting operations to have a definite list of those cache blocks to be flushed to disk and that no new blocks are added in that case...

Just thinking loud here.

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support
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Joined: Sun Dec 21, 2008 2:42 am

Re: More detailed information on flushing write cache data

Post by support »

Axel Mertes wrote:
Fri Nov 16, 2018 10:41 am
Wouldn't that mean that a flush to disk may end up running forever, if enough new disk data is coming in?
PrimoCache has its algorithm to avoid this.
Axel Mertes wrote:
Fri Nov 16, 2018 10:41 am
I would expect these manually starting operations to have a definite list of those cache blocks to be flushed to disk and that no new blocks are added in that case...
We will think about your suggestion. Thanks.
Primo Ramdisk | PrimoCache
Romex Software Support

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