Should I dedicate an entire SSD (256 GB) as L2 cache?

FAQ, getting help, user experience about PrimoCache
Post Reply
OopyDoopy
Posts: 2
Joined: Fri Nov 08, 2019 1:13 am

Should I dedicate an entire SSD (256 GB) as L2 cache?

Post by OopyDoopy »

I don't see any best practice information regarding this. Since SSD performance degrades as it fills, does it make more sense to give primocache, say, 75% of an SSD, or is the software smart enough to properly manage the space if you give it the entire SSD? Thanks for any advice.

User avatar
support
Posts: 2712
Joined: Sun Dec 21, 2008 2:42 am

Re: Should I dedicate an entire SSD (256 GB) as L2 cache?

Post by support »

PrimoCache so far is not so smart. It also depends on SSD hardware. For intel optane series, it's quite safe to use the entire SSD. Others we are not sure. For safety you may use 80%~90% of an SSD.
Primo Ramdisk | PrimoCache
Romex Software Support

User avatar
Jaga
Posts: 484
Joined: Sat Jan 25, 2014 1:11 am

Re: Should I dedicate an entire SSD (256 GB) as L2 cache?

Post by Jaga »

I reserve no less than 10% unused (un-partitioned) space at the end of all of my SSD drives, even the NVMe's. It's a "Best practice" sort of thing based on the technology, which can help with garbage collection and the times when a drive gets really full. If you were devoting an entire SSD (whichever technology) to a L2 cache, I'd say it's almost mandatory to have unused space. I haven't dealt directly with the Optane, so you can believe Support's advice with regards to them.

OopyDoopy
Posts: 2
Joined: Fri Nov 08, 2019 1:13 am

Re: Should I dedicate an entire SSD (256 GB) as L2 cache?

Post by OopyDoopy »

Made this post and forgot about it. Thanks for the input you two, I'll continue leaving some unused space (though I'll make it about 10% now).

Strela10M
Posts: 4
Joined: Mon Dec 30, 2019 5:39 pm

Re: Should I dedicate an entire SSD (256 GB) as L2 cache?

Post by Strela10M »

I was thinking, if there's going to be a SSD dedicated to be PrimoCache's cache, is it possible to use a 128gb one, or should I go for a 256gb one?
The thing is that I'm building two large computers for the company I work for to contain terabytes and terabytes of data (the history of thousands of clients, massive simulations and plans like lending plans for villas for sale in Athens, recorded calls and videos... Each byte present on both computers in case one of them fails) and I'm looking for ways to combine the stats my boss wants with the budget he's ready to give.
Last edited by Strela10M on Fri Jan 17, 2020 4:28 pm, edited 1 time in total.

User avatar
Jaga
Posts: 484
Joined: Sat Jan 25, 2014 1:11 am

Re: Should I dedicate an entire SSD (256 GB) as L2 cache?

Post by Jaga »

I think the question in your case Strela10M, is "how much of that data will be regularly accessed?". If it is a terabyte or more, then you'll want to go for the largest SSD (as a L2) that you can. If it will be infrequent or small & highly random access, then a smaller (128 GB) SSD may do fine. Primocache really shines when the data is regularly accessed, but not so much when it's something like archived data.

Post Reply