Anyone experience with PrimoCache for MSSQL-Database or Exchange acceleration ?
- Thread starter zeynel
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yes, call it snake oil...
the windows cache is pretty efficient already. that software does cache differently. block level vs. app level. which may make a difference depending on your application.
Chris
the windows cache is pretty efficient already. that software does cache differently. block level vs. app level. which may make a difference depending on your application.
Chris
I would be very sceptical to the point of calling it BS. You're basically taking RAM away from mature, highly tuned RAM-intensive and data-aware applications so that you can give it "better" disk caching.
Exchange is deliberately written to be intelligent about cache, RAM usage and disk access - you can put 50-100 users on a single SATA disk with ease, and I can tell you I have an org running 1000 users on old Exchange (07!) on a ten disk RAID 10. What good is better disk caching when it's not using the disk?
SQL has been smart about using RAM for more than two decades. Really, really big databases (50-100x memory size) can run just fine on SQL when properly set up. Taking RAM from SQL just moves it from SQL buffer cache to your block cache - and I bet SQL knows a metric frackton more about what is in the data it's caching than primocache can.
Also, let me rip apart "features" like these:
Exchange is deliberately written to be intelligent about cache, RAM usage and disk access - you can put 50-100 users on a single SATA disk with ease, and I can tell you I have an org running 1000 users on old Exchange (07!) on a ten disk RAID 10. What good is better disk caching when it's not using the disk?
SQL has been smart about using RAM for more than two decades. Really, really big databases (50-100x memory size) can run just fine on SQL when properly set up. Taking RAM from SQL just moves it from SQL buffer cache to your block cache - and I bet SQL knows a metric frackton more about what is in the data it's caching than primocache can.
Also, let me rip apart "features" like these:
- Some applications can bypass Windows cache but cannot bypass PrimoCache because PrimoCache runs at a lower level in Windows.
- Windows caches all data, while PrimoCache can cache on behalf of a specified volume in which users are interested. Given same size of system memory, the latter has a higher hit-rate.
- PrimoCache supports persistent SSD caching for mechanical hard disks, improving system boot-up time and applications loading time. Windows cache cannot.
- PrimoCache can customize write-deferred mode, while Windows cache cannot.
- PrimoCache can make use of Invisible Memory on 32-bit Windows as cache, overcoming the Windows limits on amount of system memory.
I can say that in some cases it's magic, like Remote Desktop servers. It SIGNIFICANTLY improves user experience. However, I would not recommend using write cache on ANYTHING. I've seen some data corruption.
+1 for PrimoCache+DrivePool. It is a power play and super duo compared to the mess that is Storage Spaces.
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Primo cache worked quite well for me when I had data on HDDs. It was realy noticable for Games, Git, development tools and data mining from files and even SMB shares.
I've neve used it for databases, they usually know how to use all RAM you can throw at them.
But currently I think it is usually quite pointless, if you need the throughput and latency just get yourself fastest NVME drives your pcie (and wallet) can handle (and probably pcie->nvme card if you are using DDR3) and call it a day. it will be cheaper than DDR3 (and possibly UPS) and lot safer than using write cache.
I've neve used it for databases, they usually know how to use all RAM you can throw at them.
But currently I think it is usually quite pointless, if you need the throughput and latency just get yourself fastest NVME drives your pcie (and wallet) can handle (and probably pcie->nvme card if you are using DDR3) and call it a day. it will be cheaper than DDR3 (and possibly UPS) and lot safer than using write cache.