Is the memory type of an SSD important for PrimoCache? Topic is solved

FAQ, getting help, user experience about PrimoCache
Post Reply
NemeWheel
Posts: 15
Joined: Sun Jul 07, 2019 9:35 am

Is the memory type of an SSD important for PrimoCache?

Post by NemeWheel »

Good evening everyone !

I would like to know if the memory type of an SSD (MLC, TLC, QLC etc ...) is an important parameter regarding the use of an SSD as "L2 cache"?

Currently, I use a 120 GB MLC SSD as "L2 cache". But if one day I decide to replace this SSD which is in MLC by, for example, an SSD which is in TLC / TLC 3D or even QLC, can this have an impact? And, another example, if I buy a 2 TB TLC / TLC 3D SSD on which I create a partition of a few hundred GB only dedicated to the cache for PrimoCache, is this safe?

Thanks in advance ^^

User avatar
support
Posts: 2699
Joined: Sun Dec 21, 2008 2:42 am

Re: Is the memory type of an SSD important for PrimoCache?

Post by support »

For PrimoCache, it doesn't need to know the SSD physical details. Actually, almost every storage devices can be used as "L2 cache". However, when you choose a SSD or a SSD partition as "L2 cache", you may pay attention to the following 3 things.
1) Capacity: that is L2 cache size. Usually bigger cache size, better cache performance because more data can be cached. However, a big-capacity SSD might beyond your budget. You may estimate how much data are often accessed and decide a right cache size according to your budget.
2) Speed: Faster SSD, better L2 cache performance.
3) Write lifespan: when a SSD used as cache, usually there are more writing on it compared with normal usage.
Primo Ramdisk | PrimoCache
Romex Software Support

NemeWheel
Posts: 15
Joined: Sun Jul 07, 2019 9:35 am

Re: Is the memory type of an SSD important for PrimoCache?

Post by NemeWheel »

support wrote:
Mon Jan 06, 2020 8:04 am
For PrimoCache, it doesn't need to know the SSD physical details. Actually, almost every storage devices can be used as "L2 cache". However, when you choose a SSD or a SSD partition as "L2 cache", you may pay attention to the following 3 things.
1) Capacity: that is L2 cache size. Usually bigger cache size, better cache performance because more data can be cached. However, a big-capacity SSD might beyond your budget. You may estimate how much data are often accessed and decide a right cache size according to your budget.
2) Speed: Faster SSD, better L2 cache performance.
3) Write lifespan: when a SSD used as cache, usually there are more writing on it compared with normal usage.
Hello support and thank you very much for your reply!

1) If I make an SSD partition as "L2 cache", I envisage a partition of at least 300 GB to cover almost 3 TB of HDD: good plan?

2) If I take a SATA SSD, on average, it is 560 MB / s in reading and 530 MB / s in writing: more than enough? Or should you consider opting for an NVMe?

3) Where can I see the write life of an SSD?

User avatar
Jaga
Posts: 483
Joined: Sat Jan 25, 2014 1:11 am

Re: Is the memory type of an SSD important for PrimoCache?

Post by Jaga »

NemeWheel wrote:
Mon Jan 06, 2020 8:49 am
1) If I make an SSD partition as "L2 cache", I envisage a partition of at least 300 GB to cover almost 3 TB of HDD: good plan?

2) If I take a SATA SSD, on average, it is 560 MB / s in reading and 530 MB / s in writing: more than enough? Or should you consider opting for an NVMe?

3) Where can I see the write life of an SSD?
I'll try to chime in with answers..

1) Yes, 300 GB is enough to cover a 3TB data volume, especially if it isn't full. 10% data coverage is my typical minimum, and if your 3TB drive is only half full, you are already at 20%.

2) The average SATA SSD is more than fast enough to serve as a good L2 for any conventional spinner drives. Your cache performance will of course go up with faster ones. I wouldn't however recommend a very cheap or notoriously unreliable drive (or series from a manufacturer), since most of your data will "pass through" the SSD.

3) Usually manufacturers publish expected lifetimes with product information. They also sometimes have tools that allow you to see amount of written bytes (like Samsung's Magician software). If they don't have one, you can use Crystal Disk Info to get SMART statistics on the drive, and then look at the "Total Host Writes" number on the drive. Compare that number to the advertised lifetime expectancy writes on the drive to know how far along in it's lifespan you are.

Hope that helps.

NemeWheel
Posts: 15
Joined: Sun Jul 07, 2019 9:35 am

Re: Is the memory type of an SSD important for PrimoCache?

Post by NemeWheel »

Jaga wrote:
Mon Jan 06, 2020 9:40 pm
NemeWheel wrote:
Mon Jan 06, 2020 8:49 am
1) If I make an SSD partition as "L2 cache", I envisage a partition of at least 300 GB to cover almost 3 TB of HDD: good plan?

2) If I take a SATA SSD, on average, it is 560 MB / s in reading and 530 MB / s in writing: more than enough? Or should you consider opting for an NVMe?

3) Where can I see the write life of an SSD?
I'll try to chime in with answers..

1) Yes, 300 GB is enough to cover a 3TB data volume, especially if it isn't full. 10% data coverage is my typical minimum, and if your 3TB drive is only half full, you are already at 20%.

2) The average SATA SSD is more than fast enough to serve as a good L2 for any conventional spinner drives. Your cache performance will of course go up with faster ones. I wouldn't however recommend a very cheap or notoriously unreliable drive (or series from a manufacturer), since most of your data will "pass through" the SSD.

3) Usually manufacturers publish expected lifetimes with product information. They also sometimes have tools that allow you to see amount of written bytes (like Samsung's Magician software). If they don't have one, you can use Crystal Disk Info to get SMART statistics on the drive, and then look at the "Total Host Writes" number on the drive. Compare that number to the advertised lifetime expectancy writes on the drive to know how far along in it's lifespan you are.

Hope that helps.

Hello Jaga, thank you for your answer!

1) Okay top! It seemed to me that it needed 10 to 15% data coverage as you indicated once, but I was no longer 100% sure of this information ... Thanks for the confirmation ^^

2) Ok so a SATA SSD largely does the job for an L2 cache. And yes indeed, I think it is wiser to take an SSD from a reputable brand. However, small question: is it better to take a 2 TB SSD and create a partition of about 300 GB on it dedicated to the L2 cache or rather to keep this full 2 TB SSD for gaming and take in addition an SSD M.2 NVMe only for cache?

3) The Samsung Magician software only seems to work on Samsung SSDs ... Do you have equivalent software for ALL SSDs? Because I can't find the info you say with Crystal Disk Info ...

User avatar
Jaga
Posts: 483
Joined: Sat Jan 25, 2014 1:11 am

Re: Is the memory type of an SSD important for PrimoCache?

Post by Jaga »

2) If you can afford a separate NVMe for the L2, it would be quite a bit better due to the drive characteristics. It would of course still need to be as large as you'd planned to cover the data you wanted to cache.

3) The Total Host Writes number in Crystal Disk Info is in the upper-right area, not in the list below.

NemeWheel
Posts: 15
Joined: Sun Jul 07, 2019 9:35 am

Re: Is the memory type of an SSD important for PrimoCache?

Post by NemeWheel »

Jaga wrote:
Tue Jan 07, 2020 6:09 pm
2) If you can afford a separate NVMe for the L2, it would be quite a bit better due to the drive characteristics. It would of course still need to be as large as you'd planned to cover the data you wanted to cache.

3) The Total Host Writes number in Crystal Disk Info is in the upper-right area, not in the list below.
Hello Jaga !

OK thanks for your informations. I indeed found the "Total Host Writes" on Crystal Disk Info. Considering the To that I "consumed" in writing on my current SSD compared to the TBW indicated on their technical sheet, I am quiet for a long time. And compared to my future SSD (s) that I plan to buy, I should be quiet for a very very long time ^^

Post Reply