SAS SSD vs SAS HDD in a RAID 10?
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@dave247 said in SAS SSD vs SAS HDD in a RAID 10?:
I'm currently reading all about 512n vs 512e right now but I'm not certain on what I should be going with. Any recommendations?
That's referring to sector size on the drive its self. Really doesn't matter at all.
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@travisdh1 said in SAS SSD vs SAS HDD in a RAID 10?:
@dave247 said in SAS SSD vs SAS HDD in a RAID 10?:
I'm currently reading all about 512n vs 512e right now but I'm not certain on what I should be going with. Any recommendations?
That's referring to sector size on the drive its self. Really doesn't matter at all.
I can't imagine that it doesn't matter at all...
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@dave247 said in SAS SSD vs SAS HDD in a RAID 10?:
@travisdh1 said in SAS SSD vs SAS HDD in a RAID 10?:
@dave247 said in SAS SSD vs SAS HDD in a RAID 10?:
I'm currently reading all about 512n vs 512e right now but I'm not certain on what I should be going with. Any recommendations?
That's referring to sector size on the drive its self. Really doesn't matter at all.
I can't imagine that it doesn't matter at all...
What you care about with drives are speed and capacity. What in that table makes you think Bytes per sector value or Bytes per physical sector value matter?
The piece of table you show is literally talking about how the drive electronics read and write sectors to the drive medium. Any modern OS doesn't care, and will perform, for all intents and purposes, exactly the same.
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@travisdh1 said in SAS SSD vs SAS HDD in a RAID 10?:
@dave247 said in SAS SSD vs SAS HDD in a RAID 10?:
@travisdh1 said in SAS SSD vs SAS HDD in a RAID 10?:
@dave247 said in SAS SSD vs SAS HDD in a RAID 10?:
I'm currently reading all about 512n vs 512e right now but I'm not certain on what I should be going with. Any recommendations?
That's referring to sector size on the drive its self. Really doesn't matter at all.
I can't imagine that it doesn't matter at all...
What you care about with drives are speed and capacity. What in that table makes you think Bytes per sector value or Bytes per physical sector value matter?
The piece of table you show is literally talking about how the drive electronics read and write sectors to the drive medium. Any modern OS doesn't care, and will perform, for all intents and purposes, exactly the same.
Isn't there potentially less usable storage space with 512e? Isn't 512n older than 512e and aren't there slight performance differences? I read stuff online but I try to steer clear of random people saying things on random forums since there's no way to tell if they know what they are talking about. I'm reading through this document right now in hopes of leading me to the best decision.
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@dave247 said in SAS SSD vs SAS HDD in a RAID 10?:
@travisdh1 said in SAS SSD vs SAS HDD in a RAID 10?:
@dave247 said in SAS SSD vs SAS HDD in a RAID 10?:
@travisdh1 said in SAS SSD vs SAS HDD in a RAID 10?:
@dave247 said in SAS SSD vs SAS HDD in a RAID 10?:
I'm currently reading all about 512n vs 512e right now but I'm not certain on what I should be going with. Any recommendations?
That's referring to sector size on the drive its self. Really doesn't matter at all.
I can't imagine that it doesn't matter at all...
What you care about with drives are speed and capacity. What in that table makes you think Bytes per sector value or Bytes per physical sector value matter?
The piece of table you show is literally talking about how the drive electronics read and write sectors to the drive medium. Any modern OS doesn't care, and will perform, for all intents and purposes, exactly the same.
Isn't there potentially less usable storage space with 512e? Isn't 512n older than 512e and aren't there slight performance differences?
Yes, there are performance differences. If you can actually notice them in real usage, then you'll be the first I've heard of it.
I read stuff online but I try to steer clear of random people saying things on random forums since there's no way to tell if they know what they are talking about. I'm reading through this document right now in hopes of leading me to the best decision.
White paper = sales brochure. At best, they're trying to confuse you in the hopes that you'll buy the more expensive stuff.
The performance difference is so small as to be statistically irrelevant.
IOPS will be the same, and it's IOPS that we really care about for servers.
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@travisdh1 said in SAS SSD vs SAS HDD in a RAID 10?:
@dave247 said in SAS SSD vs SAS HDD in a RAID 10?:
@travisdh1 said in SAS SSD vs SAS HDD in a RAID 10?:
@dave247 said in SAS SSD vs SAS HDD in a RAID 10?:
@travisdh1 said in SAS SSD vs SAS HDD in a RAID 10?:
@dave247 said in SAS SSD vs SAS HDD in a RAID 10?:
I'm currently reading all about 512n vs 512e right now but I'm not certain on what I should be going with. Any recommendations?
That's referring to sector size on the drive its self. Really doesn't matter at all.
I can't imagine that it doesn't matter at all...
What you care about with drives are speed and capacity. What in that table makes you think Bytes per sector value or Bytes per physical sector value matter?
The piece of table you show is literally talking about how the drive electronics read and write sectors to the drive medium. Any modern OS doesn't care, and will perform, for all intents and purposes, exactly the same.
Isn't there potentially less usable storage space with 512e? Isn't 512n older than 512e and aren't there slight performance differences?
Yes, there are performance differences. If you can actually notice them in real usage, then you'll be the first I've heard of it.
I read stuff online but I try to steer clear of random people saying things on random forums since there's no way to tell if they know what they are talking about. I'm reading through this document right now in hopes of leading me to the best decision.
White paper = sales brochure. At best, they're trying to confuse you in the hopes that you'll buy the more expensive stuff.
The performance difference is so small as to be statistically irrelevant.
IOPS will be the same, and it's IOPS that we really care about for servers.
ok then, where do you go to get technical information on the different technologies like this?
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The PM863A's at xByte are refurbs. They are @ $1,299 each and include the correct tray with 1 year warranty. If you buy them in a current gen server they include Dell's NBD onsite warranty. If you need a better SLA on the warranty we can do that as well!
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We also have the 3.84TB MU TLC NVMe as well (PM1725a). Not too much more @ $1,999 each. The R740XD will allow up to x24 NVMe drives and the R640 will allow up to x8 NVMe's.
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@bradfromxbyte said in SAS SSD vs SAS HDD in a RAID 10?:
We also have the 3.84TB MU TLC NVMe as well (PM1725a). Not too much more @ $1,999 each. The R740XD will allow up to x24 NVMe drives and the R640 will allow up to x8 NVMe's.
Do you put those NVMe cards in a RAID config or what? I'm looking at a R640 build right now and I saw one of those 3.84TB NVMe cards was like $5K
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It's not a hardware raid. It bypasses the perc completely and goes from the back plane to the proc directly. Any management is done via OS.
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@dave247 said in SAS SSD vs SAS HDD in a RAID 10?:
@pete-s said in SAS SSD vs SAS HDD in a RAID 10?:
@dave247 said in SAS SSD vs SAS HDD in a RAID 10?:
ok, well if I want to do a RAID 1 then, I've got these as options as they are almost 4TB:
- 3.84TB SSD SAS Read Intensive 12Gbps 512n 2.5in Hot-plug Drive, PX05SR,1 DWPD,7008 TBW - $4,673.84 /ea.
- 3.84TB SSD SAS Read Intensive 12Gb 512e 2.5in Hot-plug Drive, PM1633a,1 DWPD,7008 TBW - $4,391.49 /ea.
- 3.84TB SSD SATA Read Intensive 6Gbps 512n 2.5in Hot-plug Drive, PM863a - $3,262.09 /ea.
- 3.84TB SSD SATA Read Intensive 6Gbps 512e 2.5in Hot-plug Drive, S4500,1 DWPD,7008 TBW - $3,262.09 /ea.
And I could toss out the H740P and go back to the H330
You pay a severe Dell tax on those prices.
PM863a is a Samsung drive and the real price is around $1500.
S4500 is Intel but older slower model as the newer one is S4510. Real price on the newer model is around $1500.Don't have prices on PX05SR (Toshiba) or PM1633a (Samsung) but similar drive HGST Ultrastar SS300 is around $2800, Seagate 1200.2 is around $2500.
With real price I mean what you pay if you buy one drive from just about anywhere.
I wouldn't waste any money on SAS 12Gbps drives (unless you need dual port) because if you need maximum performance U.2 NVMe is what you want. Don't be fooled by "read intensive" either - 1 DWPD means you can write 3.8TB per day for 5 years.
Damn Dell prices... They are so high. I see on xbyte, the PM863a is a lot cheaper, though I can't tell if that's a used/refurb part. What other places would you suggest I look?
Used and refurb are different. Used has been used, refurb has not.
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@bradfromxbyte said in SAS SSD vs SAS HDD in a RAID 10?:
It's not a hardware raid. It bypasses the perc completely and goes from the back plane to the proc directly. Any management is done via OS.
oh, well I want redundancy..
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@scottalanmiller said in SAS SSD vs SAS HDD in a RAID 10?:
@dave247 said in SAS SSD vs SAS HDD in a RAID 10?:
@pete-s said in SAS SSD vs SAS HDD in a RAID 10?:
@dave247 said in SAS SSD vs SAS HDD in a RAID 10?:
ok, well if I want to do a RAID 1 then, I've got these as options as they are almost 4TB:
- 3.84TB SSD SAS Read Intensive 12Gbps 512n 2.5in Hot-plug Drive, PX05SR,1 DWPD,7008 TBW - $4,673.84 /ea.
- 3.84TB SSD SAS Read Intensive 12Gb 512e 2.5in Hot-plug Drive, PM1633a,1 DWPD,7008 TBW - $4,391.49 /ea.
- 3.84TB SSD SATA Read Intensive 6Gbps 512n 2.5in Hot-plug Drive, PM863a - $3,262.09 /ea.
- 3.84TB SSD SATA Read Intensive 6Gbps 512e 2.5in Hot-plug Drive, S4500,1 DWPD,7008 TBW - $3,262.09 /ea.
And I could toss out the H740P and go back to the H330
You pay a severe Dell tax on those prices.
PM863a is a Samsung drive and the real price is around $1500.
S4500 is Intel but older slower model as the newer one is S4510. Real price on the newer model is around $1500.Don't have prices on PX05SR (Toshiba) or PM1633a (Samsung) but similar drive HGST Ultrastar SS300 is around $2800, Seagate 1200.2 is around $2500.
With real price I mean what you pay if you buy one drive from just about anywhere.
I wouldn't waste any money on SAS 12Gbps drives (unless you need dual port) because if you need maximum performance U.2 NVMe is what you want. Don't be fooled by "read intensive" either - 1 DWPD means you can write 3.8TB per day for 5 years.
Damn Dell prices... They are so high. I see on xbyte, the PM863a is a lot cheaper, though I can't tell if that's a used/refurb part. What other places would you suggest I look?
Used and refurb are different. Used has been used, refurb has not.
I thought refurb could have been used.. doesn't refurb mean it's been ordered and returned but not necessarily used?
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@phlipelder said in SAS SSD vs SAS HDD in a RAID 10?:
NV Cache is important. Having battery backed cache means there's a maintenance item in the batteries. They wear out or outright die at some point thus impacting performance because the RAID engine will flip over to Write-Through when they disappear.
Agreed. Battery backed cache is fine from a safety standpoint, but terrible from a "dealing with it in real life" standpoint. Had one die on us last week. Result? Critical server could not be rebooted without manual intervention!
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@pete-s said in SAS SSD vs SAS HDD in a RAID 10?:
NVMe drives are many hundreds of percent faster, have much higher IOPS, lower latency and the software stack is much more optimized.
But are more expensive when typically traditionally SSDs are already faster than necessary. And NVMe needs RAID, too. So RAID isn't dead, in fact NVMe has revitalized it.
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@phlipelder said in SAS SSD vs SAS HDD in a RAID 10?:
NVMe is nowhere near as mature a technology as SAS is. The resilience that's built-in to SAS is just not there yet with NVMe. That's why Hyper-Converged is such a big thing.
Local attached storage, such as NVMe, shared out across nodes with resilience built-in at the node local storage level and up.
Most hyperconvergence uses both NVMe and SAS or SATA SSDs. HC was a big driver long before NVMe became widely available. HC is pretty old, NVMe is decently new.
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@dave247 said in SAS SSD vs SAS HDD in a RAID 10?:
@travisdh1 said in SAS SSD vs SAS HDD in a RAID 10?:
@dave247 said in SAS SSD vs SAS HDD in a RAID 10?:
@travisdh1 said in SAS SSD vs SAS HDD in a RAID 10?:
@dave247 said in SAS SSD vs SAS HDD in a RAID 10?:
@travisdh1 said in SAS SSD vs SAS HDD in a RAID 10?:
@dave247 said in SAS SSD vs SAS HDD in a RAID 10?:
I'm currently reading all about 512n vs 512e right now but I'm not certain on what I should be going with. Any recommendations?
That's referring to sector size on the drive its self. Really doesn't matter at all.
I can't imagine that it doesn't matter at all...
What you care about with drives are speed and capacity. What in that table makes you think Bytes per sector value or Bytes per physical sector value matter?
The piece of table you show is literally talking about how the drive electronics read and write sectors to the drive medium. Any modern OS doesn't care, and will perform, for all intents and purposes, exactly the same.
Isn't there potentially less usable storage space with 512e? Isn't 512n older than 512e and aren't there slight performance differences?
Yes, there are performance differences. If you can actually notice them in real usage, then you'll be the first I've heard of it.
I read stuff online but I try to steer clear of random people saying things on random forums since there's no way to tell if they know what they are talking about. I'm reading through this document right now in hopes of leading me to the best decision.
White paper = sales brochure. At best, they're trying to confuse you in the hopes that you'll buy the more expensive stuff.
The performance difference is so small as to be statistically irrelevant.
IOPS will be the same, and it's IOPS that we really care about for servers.
ok then, where do you go to get technical information on the different technologies like this?
From IT, not from vendors. Just like in medicine you'd get medical advice from doctors, not drug companies. The job of a vendor is to sell you something you'd not buy on your own. The job of IT is to advise you on what to do.
White papers are tools from vendors, and IT should take them with a grain of salt. They are useful for listing specs, but not for learning about technology or techniques.
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@bradfromxbyte said in SAS SSD vs SAS HDD in a RAID 10?:
It's not a hardware raid. It bypasses the perc completely and goes from the back plane to the proc directly. Any management is done via OS.
Has to for stuff that fast. Only software RAID can keep up!
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@dave247 said in SAS SSD vs SAS HDD in a RAID 10?:
@bradfromxbyte said in SAS SSD vs SAS HDD in a RAID 10?:
It's not a hardware raid. It bypasses the perc completely and goes from the back plane to the proc directly. Any management is done via OS.
oh, well I want redundancy..
- What does that have to do with the statement above?
- No, you don't. no one ever "wants" redudancy. That's not a thing anyone should rationally desire. Redundancy is always a tool to achieve a desire, never a desire itself. You should ask yourself what your goal is. We assume you mean reliability, and are using redundancy accidentally as a proxy to mean reliability. But it is REALLY important not to do this, because vendors prey on that mistake left and right and it is amazing how many systems lose data because of that mistake.
