I'm not a data hoarder (well, a bit, perhaps) but I like to keep stuff locally, so I have a few larger drives, and you know what? They're hard to find, and sometimes bloody slow.
There's no absolute fix, but at least I can remind myself not to buy those f* SMR drives!
SMR Drives
Do. Not. Buy. Them. I accidentally bought one (a Toshiba) and it's a slow pain in the ass.
Some drives may perform better if you use 64 kB clusters instead of 4 kB clusters. The only way to check that for yourself is emptying the drive and reformatting it. Sigh...
(I've done some benchmarking further down.)
Can you buy another 'color' and use them as your desktop drive?
It's complicated, but you should be fine. These days, Red and Purple HDDs seem to be way cheaper than the Blue versions, so yeah, why not.
Just make sure you got the proper drive.
Seagate vs WD
I have had some bad experience with Seagate in the past, so my perception is colored (joke intended, haha). I don't think it matters that much these days, but their 3 TB drives were lemons. I owned four, and all of them failed.
Suggestions:
Boot drive: NVME > SSD > WD Black
Databases with lots of writes / Torrents / Video editing too big for SSD: WD Black
Generic (avoid SMR drives and watch the pricing): WD Blue ~ WD Purple ~ WD Red
Background storage: whatever (even SMR if you're patient enough)
WD Drives (and types of drives)
Kudos to their marketing department. I like those colors. Grab a HDD with the proper color and be done. Although it might not matter that much...
(I don't like their sneaking in of SMR drives between the regular CMR drives.)
WD Blue - Generic Desktop
(Seagate Barracuda)
Regular usage, come in CMR and SMR. Don't use SMR unless you have no other choice. Never put a database on an SMR drive.
Desktop usage: work fine as primary drive, as long as they are not SMR
In my home server, the Blues would copy very large files at approx. 100 MB/sec
WB Black - Performance Desktop
(Seagate Firecuda)
My preferred drive. I still have a 2 TB WD Black that runs like a rocket.
Desktop usage: best for everything
WD Red - NAS
(Seagate Ironwolf)
Optimized for reading. For NAS applications. Has some optimizations to handle NAS usage, and will quicker time out when they cannot read a sector. Might last longer.
Reds are supposed to have vibration detection, and thus suitable for mounting a lot in close proximity of one another.
Pro versions are faster and supposed to last longer.
Desktop usage: okay, but be aware that these are quicker to give up on a poor quality sector than a regular desktop drive, and may be a little slower.
In my homeserver, the Reds would copy very large files at approx. 75 MB/sec
WD Purple - Surveillance
(Seagate Skyhawk)
Optimized for writing. Might last longer.
Desktop usage: may be a little slower than the other drives. Make sure you don't end up with an SMR drive!
WD Green - Energy Saving
(Seagate - no equivalent)
No longer made (?). Seems to have merged with the WD Blue line.
Desktop usage: not suitable as a boot / main drive as they spin down a lot.
WD Gold - Enterprise
(Seagate Exos)
Expensive, intended for 24/7 usage.
Desktop usage: why pay that much?
Can you identify SMR drives?
Yes. Look for the spec sheets... and hope the vendors are honest.
If you own two similar drives, one with and one without SMR, you may be able to use Crystal Diskmark to identify them. I own two nearly identical (product number wise) 4 TB drives which are very different beasts internally.
- WD Blue 4 TB - WD40EZRZ-00WN9B0 - CMR
- WD Blue 4 TB - WD40EZRZ-00GXCB0 - SMR
It appears to be possible to use Crystal Diskmark to identify SMR drives, but it's a bit counter intuitive...
Using Crystal Diskmark to detect an SMR spinner
By pure (bad) luck I have two WB Blue 4 TB drives, bought within a couple of months. One seems to be a CMR, the other one an SMR.
Crystal Diskmark 'Default' Settings
Quick, fast, dirty:
Settings / Default
Profile / Default + Mix
Profile / Read & Write + Mix
1 tests, 1 GB, R 70% W 30%
Note that I used these settings on two different machines, and with drives that had quite a bit of stuff on 'em. Unfortunately, the results were not very useful for identifying an SMR drive.
Crystal Diskmark 'Real World' Settings
Now the default settings don't work very well. SMR drives are build in such a way that they will behave and perform reasonably well, until they start to shuffle their files around. By using somewhat different settings we can hammer them with Crystal Diskmark to show their true nature:
Settings / Default
Profile / Real World + Mix
Profile / Read & Write + Mix
5 tests, 4 GB, R 50% W 50%
Disks tried
WD Black NVME PCIE4 on Dev5
- The fastest. How could I ever live without an NVME drive?
WD Blue NVME PCIE3 on Dev5
- This is a secondary NVME drive on a PCIe3 slot. (One of the limitations of my mainboard.)
- It's a little faster on 4k random reads, which is a bit surprising.
WD Black 2 TB CMR on Dev5
- It doesn't show clearly in the numbers, but this drive 'feels' a lot faster than the 8 TB SMR drive.
- The mere 135 MB/sec for Mix indicates it's not an SMR (I know it isn't) but it isn't impressive.
- So even when hammered, it still writes 180 MB/sec, and does random seek+write in 2808 uS.
- It's a bit slow in the search department though. Though not as slow as some other drives...
- This one could accidentally be identified as an SMR, but it is a CMR, and it actually performs better than the numbers suggest. The drive doesn't like Crystal Diskmark's algoritms, I guess 😅
WD Blue 8 TB CMR on Dev5
- Yes, many people report that their 8 TB WD80EAAZ-00BXBB0 is a CMR, and so do the WD specifications
- A faster read but a slower write than the much older WD Black 2 TB CMR drive. But let's be fair, performance appears ok. I suspect some internal translations, invisible to the user. It may be wise to use larger cluster sizes for this drive.
- Now, if it IS an SMR drive, it should get quite a bit slower when I hit 25% or so... Definitely at 50%. So, I tried that. I filled the drive at 60%, and ran the Real World profile again. There was no spectacular decrease, so I suppose it's a CMR drive after all.
WD Blue 4 TB CMR on Media6
Another drive that isn't entirely happy with mixed mode.
Seeks are twice as slow as writes for random access, pretty normal for a CMR drive.
WD Blue 4 TB SMR on Media6
- And here we go. It's a bit faster in reading and writing, but when you hit a Mix of read and write the performance about halves, where with a CMR drive it's typically still at 70% or better.
- I still find it weaird that writing is that much faster than reading. It appears the drive firmware does its utter best to get rid of that data before reading anything. Perhaps reads stay inside the cache, so the drive uses that time to get rid of its writes? I don't know, but thus far all SMR drives I've seen showed this behavior. Weird.
Toshiba P300 4 TB SMR on Dev5
- Yeah, Crystal Diskmark isn't very useful here. It reports this drive to be faster than the WD Black 2 TB, but trust me, in real life it is not! This drive is an absolute lemon, and you can see that reflected in the Mix score...
- Look at those poor 'Mix' numbers at 90% reads! This drive seriously doesn't like a mix of reads and writes. I suspect this drive has a very poor caching algorithm.
- Using the Real World settings some of the indicators become more clear. Yes, it's reasonably fast on reads, writes, and IOPS, but the performance with a mixed load (higher is better), as well as the very slow RND4K score (higher is worse) indicate an underlying problem.
- Either the drive is a very slow seeker in general, or it is an SMR drive... (It is.)
Conclusion
1. The SMR variants are actually performing better than expected, but what Crystal Diskmark doesn't show is the incidental 'freeze' that may happen when the drive is doing some internal bookkeeping during writing, especially when copying massive sets of data, like the full drive contents from one drive to another.
2. When using the 'Real World' profile above, a low 'Mix' value shows that either the drive doesn't have the best caching algoritm, or it is an SMR drive.
3. The second indicator is the RND4k uS score. High search times typically line up with SMR drives.
4. The approach above may not work with smarter firmware. What's going to stop a drive from allocating new subsections of shingles, until there are no shingles left, to keep the speed up? Ie. 1xxx -> 11xx -> 111x -> 1111, that's four writes not being affected by SMR.
Software detection...
... is going to be hard, if even possible. Whatever you do, should a. bypass or fill up the cache, b. use as many shingles as possible, c. intermittently write blocks of data to test for continuous writing speed. This lies in the same realm as SSD garbage collection detection.
But... does the exact mechanism matter? We just know that, at some point, performance falls down a cliff, and that's the only thing we're interested in. Even if garbage collection is supersmart, it only helps us if the drive has nothing to do, and that's exactly the moment we don't care about drive speed 😅
Drives I know about
In use, or used...
Some of these are getting quite old, and have been in use for several years.
Dev3
WD Black 2 TB - NVME
WD Blue 2 TB - NVME
WD Black 2 TB - CMR
- quite an old one by now, has seen some serious heavy usage over time as boot and temp drive
WD Purple 4 TB - WD43PURZ - CMR
WD Blue 8 TB - WD80EAAZ-00BXBB0 - CMR
DT7
? - NVME
WD Black 1 TB - CMR
- another one that is seemingly lasting forever
Media6
Samsung 840EVO 120 GB - SSD
WD Blue 4 TB - WD40EZRZ-00WN9B0 - CMR
- it copies large files in my home server at approx 100 MB/sec
- Crystal Diskmark shows that the xxxN9B0 performs like expected from a CMR drive
WD Blue 4 TB - WD40EZRZ-00GXCB0 - SMR
- these drives with C7K in their serial number are both reported as CMR and SMR
- it copied large files in my home server at approx 100 MB/sec or even a little faster
- Crystal Diskmark shows half the write speed of the xxxN9B0 unit in random writes, so this is an SMR drive 😒 sneaked into the WD Blue line by WD.
WD Red 4 TB - WD40EFRX-68WT0N0
- bought used, still runs
WD Red 4 TB - WD40EFRX-68WT0N0
- bought used, is flaky (I shouldn't be using this one and will replace it soon)
Seagate Barracuda 2 TB - ST2000DL003
- refurbished, it's predecessor failed within warranty
Not in use
Seagate Skyhawk 4 TB - CMR
Toshiba P300 4 TB - HDW240 - SMR
- A serious SMR lemon
WD Green 1 TB
Seagate Barracuda 2 TB - CMR
Seagate Barracuda 2 TB - CMR
Seagate Barracuda 2 TB - CMR
Bad
Seagate Barracuda 3 TB - CMR
- Yeah, one of the lemons
No comments:
Post a Comment