Best settings for cache?

FAQ, getting help, user experience about PrimoCache
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Jaga
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Re: Best settings for cache?

Post by Jaga »

Do you have any other drive acceleration software running Myg? Things like Samsung's RAPID try to do similar speed-up routines, and aren't good to run alongside Primocache.

Also, disable Windows fast boot (or any other motherboard fast boot features). Prefetch hasn't failed me yet in many years, but it could if you have other software or features interfering with boot time routines.
Myg
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Re: Best settings for cache?

Post by Myg »

Nope, I don't have any other drive acceleration running. I am using a WD Blue SN550 NVMe SSD with the WD dashboard and it has Trim and Write-Cache enabled by default.

After using INFINITE as a setting for the Defer-Write for a while I suddenly experienced programs freezing and causing mayhem with my windows. I tried to lower the number but it didn't have any effect. I had to remove the cache and uninstall primocache for it to go away. Not sure what did it so I am going to run it without primocache for a bit. All I wanted from primocache was to extend the life of my SSD so I hope it will be usable again in the future for me.
Myg
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Re: Best settings for cache?

Post by Myg »

Re-installed and activated a week ago. Set my L1 cache to 32GB, Block size 4KB, Enable Defer-Write to INFINITE latency, no Prefetch/etc.

I have not suffered any problems as before. I suspect my issues were to other hardware failing (which I removed).

Primocache seems to be stable as a rock.
Aaron
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Re: Best settings for cache?

Post by Aaron »

Hello and sorry for "necropostin".
Just installed trial version of Primocache on my old i3 6GB ram with old 120gb SSD. So one system drive partition is used.
Primocache is working as i expected.

Settings are:
- 4kb cluster & block size
- Defer-Writes set to 10s in "intelligent mode"
- Prefetch last cache

5 minutes idle time after windows started, then reboot. Managed to get 15% cache hit rate.
Funny thing was when my Antivirus updated its signatures, the cache hitrate went to 25%. In this situation, if i enable "Lock Cache Content" does those AV signatures gets loaded from the file when PrimoCache writes to a disk when shutting down or rebootin?

Just a few questions:
1) How does this prefetcher feature work? Windows does have it own. Primocache saves latest prefectch (locked) on the disk. Does this actually decrease perfomance during bootup sequence? Because Primo has to have it own kernel mode I/O drive for that?

2) Windows file cache vs Primo block level cache, how does it actually differs, especially when 8GB or more system memory?
3) Does Primo "override" windows own API or are all I/O redicted by its own driver?
4) Is Primo compatible with third party defraggers?
5) Is "Fast Boot" feature recommended to disable or enabled
6) Is "Sysmain" recommended to disabled or enabled

Regards,
-Aaron
InquiringMind
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Re: Best settings for cache?

Post by InquiringMind »

Welcome to the forums Aaron,
Aaron wrote: Sun Aug 15, 2021 11:56 amIn this situation, if i enable "Lock Cache Content" does those AV signatures gets loaded from the file when PrimoCache writes to a disk when shutting down or rebootin?
Enabling pre-fetch does not result in actual data being stored, but instead the block numbers that the data came from. These blocks are then read on startup, meaning that any changes in data since they were first cached, are included.

So in theory, your most current AV signatures would be loaded during pre-fetch even if it was locked. In practice, it depends on the internal workings of your AV. If the signature files are overwritten during an update (i.e. the same files are reused), then the new data should occupy the same blocks as the previous (with an SSD, write-leveling will redirect to a new SSD block but this happens at firmware level so will still appear to Windows as the same block). If an AV update results in new signature files though, these will likely occupy different blocks and therefore not be included in a "locked pre-fetch".
Aaron wrote: Sun Aug 15, 2021 11:56 am1) How does this prefetcher feature work? Windows does have it own. Primocache saves latest prefectch (locked) on the disk. Does this actually decrease perfomance during bootup sequence? Because Primo has to have it own kernel mode I/O drive for that?
Pre-fetch will store a list of block numbers that were previously (L1) cached - these are held in a file in the Prefetch folder labeled pf{cache task number}.pf. This file is then read shortly after the next Windows startup - so yes, there will be a performance impact when this happens.
Aaron wrote: Sun Aug 15, 2021 11:56 am2) Windows file cache vs Primo block level cache, how does it actually differs, especially when 8GB or more system memory?
Windows' own cache works at file level rather than block level. It can be bypassed in certain cases (e.g. by disk benchmarking software) while PrimoCache cannot, and it will give up memory to applications (losing cached data) while PrimoCache will not. PrimoCache provides more control (ability to set cache size, cache block size, read/write policy, defer write delay). If you are using system-level compression (NTFS or Windows 10' Compact OS) then PrimoCache will cache the compressed data (I think, but aren't sure, that Windows file cache will store the uncompressed data).

If you have limited system memory (i.e. you are using most of it) then Windows' file cache will likely provide better performance. If you have plenty of memory to spare, then PrimoCache will likely do better.
Aaron wrote: Sun Aug 15, 2021 11:56 am3) Does Primo "override" windows own API or are all I/O redicted by its own driver?
Windows' file cache continues running and will take precedence over PrimoCache (i.e. PrimoCache L1 will initially duplicate Windows file cache data as disk reads occur, but it will not see any reads fulfilled by Windows' cache so in the long term the two caches will store different data). There is no easy way to prevent this, which is a downside.
Aaron wrote: Sun Aug 15, 2021 11:56 am4) Is Primo compatible with third party defraggers?
All defraggers use the same Microsoft defragmentation API and MyDefrag works OK in my experience (by working, I mean not filling PrimoCache with data during a defrag).
Aaron wrote: Sun Aug 15, 2021 11:56 am5) Is "Fast Boot" feature recommended to disable or enabled
I don't use it so can't comment.
Aaron wrote: Sun Aug 15, 2021 11:56 am6) Is "Sysmain" recommended to disabled or enabled
SysMain/SuperFetch would (at best) overlap with Pre-Fetch and given its tendency to lock disks up, would be better disabled.
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