PCIe SSD vs SAS SSD
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@scottalanmiller said:
Rarely but they are seen. At least once a fortnight, I would guess, I speak to someone looking at the quad processor boxes or larger (roughly double to quadruple the standard SMB server size.) Still rare, but not super rare. Once you get past the capacity needs of a single standard box it often, nearly always in fact, makes sense to scale vertically until you just can't stay in a single box anymore. This is why enterprises often use massive UNIX and mainframe systems. The power in a single box is just so valuable.
Sure, if you're starting from scratch or it's refresh time anyhow, but in SMB that's rarely the case. That said, the recent example on Spiceworks where this question/conversation spawned from, shows that re-engineering your current setup with more RAM and a better disk subsystem is often very viable, and probably overlooked by many SMBs.
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@KOOLER said:
@Dashrender said:
I wasn't aware that PCIe SSD were as reliable as RAID based SAS SSD until I ran across a thread on SW this morning.
These devices are (or at least were) normally more than 100% more than the cost of similar sized SAS SSD and the accompanying RAID controller.
Now obviously we IT folks in general have found that single RAID controllers are reliable enough to not warrant having a backup within the same chassis, we find that it's just as likely to have a whole die as to have the RAID controller die, so instead of backing up the RAID controller we backup the whole system to cover those situations.
I've done a little reading now, it seems that the resiliencies of PCIe SSDs are approximately equivalent to a RAIDed setup, and the controller is at least equivalent to normal RAID controllers.
As the costs come down, these seem like the clear winner.
What is your experience?
We recommend using PCIe and newer NVMes for cache. You can go all-flash of course but that's more expensive than desired typically. Back to SAS SSDs they are overpriced IMHO compared to their SATA siblings.
Do you recommend SATA SSDs over SAS SSDs because the price point vs performance/failure rate rarely warrants it?
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SATA SSDs often make sense because they are cheaper and the protocol benefits of SAS really are not there in the same ways for SSDs.
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@Dashrender said:
@KOOLER said:
@Dashrender said:
I wasn't aware that PCIe SSD were as reliable as RAID based SAS SSD until I ran across a thread on SW this morning.
These devices are (or at least were) normally more than 100% more than the cost of similar sized SAS SSD and the accompanying RAID controller.
Now obviously we IT folks in general have found that single RAID controllers are reliable enough to not warrant having a backup within the same chassis, we find that it's just as likely to have a whole die as to have the RAID controller die, so instead of backing up the RAID controller we backup the whole system to cover those situations.
I've done a little reading now, it seems that the resiliencies of PCIe SSDs are approximately equivalent to a RAIDed setup, and the controller is at least equivalent to normal RAID controllers.
As the costs come down, these seem like the clear winner.
What is your experience?
We recommend using PCIe and newer NVMes for cache. You can go all-flash of course but that's more expensive than desired typically. Back to SAS SSDs they are overpriced IMHO compared to their SATA siblings.
Do you recommend SATA SSDs over SAS SSDs because the price point vs performance/failure rate rarely warrants it?
Scott had replied below. Key point with commodity hardware is - economy of scale kicks in, price goes down dramatically so typically more expensive stuff has not that great $/TB or $/IOPS rate compared to COTS one.
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@scottalanmiller said:
SATA SSDs often make sense because they are cheaper and the protocol benefits of SAS really are not there in the same ways for SSDs.
So this brings up @DustinB3403 question of best practice or more aptly as you @scottalanmiller said implementation patterns - which ones as generically as you can be would go which way. I suppose it might be easier to say 'in these set of circumstances (list 1-4) you do this, generally in the rest you do that.'
