SSD labeled as "caching SSDs"?

[jaydee]

I am thinking about installing a small SSD (32 GB would be plenty), for an OS drive for my server (HP Proliant 4-bay). It's on 24/7, but in sleep mode a lot of the time. It's very slowing waking up on the 250GB mech HDD, of which it's using very little space of. My data is stored in a RAID 1 config of two 1TB drives.

So I was looking at small SSDs as really this would only host the OS and some server-based applications, and I see a lot of "SSD caching" devices in the 30GB range for ~$40-50. Is there any reason I would not be able to use one of these as an OS drive? What makes it a "caching" SSD as opposed to a "regular" SSD? Just some extra layer of firmware/software or what?

Thanks

 

[BonzaiDuck]

I am thinking about installing a small SSD (32 GB would be plenty), for an OS drive for my server (HP Proliant 4-bay). It's on 24/7, but in sleep mode a lot of the time. It's very slowing waking up on the 250GB mech HDD, of which it's using very little space of. My data is stored in a RAID 1 config of two 1TB drives.

So I was looking at small SSDs as really this would only host the OS and some server-based applications, and I see a lot of "SSD caching" devices in the 30GB range for ~$40-50. Is there any reason I would not be able to use one of these as an OS drive? What makes it a "caching" SSD as opposed to a "regular" SSD? Just some extra layer of firmware/software or what?

Thanks

I don't know rightly if that feature is chipset-dependent, but I think it is. It was introduced for the Z68/skt-1155 chipset. There was some speculation that similar Marvel chipsets used with those boards were capable of the same thing, but I never found any link sporting the software layer that would do it.

You didn't say what motherboard, processor or chipset is in the ProLiant, but I'd be skeptical if you can do that with your server. I could suspect that it MIGHT be possible with an Intel SATA controller of recent vintage, but I wouldn't know. As for other controllers, you can do the leg-work, and I won't promise you'll find anything that would allow it.

In any event, the drives or arrays that can be accelerated must be on the same controller as the caching SSD.

 

[jaydee]

Sorry, I wasn't specific enough. I'm not trying to actually use the "caching/acceleration" feature, I'm wondering if I can use it as a plain boot drive, install/run the OS and couple small apps on it.

 

[BonzaiDuck]

Sorry, I wasn't specific enough. I'm not trying to actually use the "caching/acceleration" feature, I'm wondering if I can use it as a plain boot drive, install/run the OS and couple small apps on it.

Oh! Sure -- now I understand. I have a WHS-2011 box, and the OS uses maybe 60 GB, while the smallest drive I had was maybe a 320GB and I didn't want to bother pooling the drivespace with my 1TB units.

If you were planning to do that, I'd actually pick an SSD that ISN'T expressly marketed as a "caching solution."

I've been looking at a Mushkin 60GB SSD to swap out for my old Patriot Pyro of the same size. They may have been priced around $80, and you can find them at the Egg if you just do the search. They're rated for sequential reads exceeding maybe 530 MB/s, and the write-rate is still phenomenally close to that. You can analyze the customer-reviews and other "intel" as you choose. My feeling, the Mushkins are probably fine despite the frequency of the "complaint-rate." The one-Egg ratings are always biased upwards.

There's also probably nothing wrong with using an SSD promoted for "caching." But you'll buy the specs associated with it. Hopefully your server has SATA-III ports.

 

[jaydee]

Thanks. The problem with WHS 2011 (which I currently have running), is that it will not install on a drive less than 160GB by default. I've seen some hacks around it, but I don't think it's worth the trouble, so I'm planning on switching over to Debian, Ubuntu or CentOS, haven't decided yet.

I'm specifically wondering about the "Cache" ones because those are readily available for under $50. I'm pretty sure my server only supports SATA II, so I'm not sure if the Mushkin 60GB would be of actual benefit for ~66% more cost anyway.

 

[dave_the_nerd]

There's no real difference between "cache" SSDs and other types.

With the caveat that they're a bit slower than their full sized brethren (fewer NAND channels). But they're still faster than a platter HDD.

I am using a Sandisk 32GB ReadyCache as a boot drive in my HTPC (connects to a NAS hosting all the media) and it works fine. For the same money, I could have gotten a 320GB HDD, but I'm using <20GB, so what's the point? If I'm waiting for the machine to boot, it's because I want to watch TV, so it might as well be fast.

 

[dbcooper1]

I think the 'caching' SSDs are just overprovisioned so that you only have access to about half of real capacity; they do this so they don't wear out since they're constantly being written to because of their nature in this application. I'm not aware of anything specifically special about them otherwise except possibly including some software that performs the caching function.