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Once bitten, twice shy...I got hit hard a long time ago by some proprietary backup software that created files only it could read, and (I guess) one misplaced bit at the worst possible location was enough to make the entire file unusable. Of course that's when I needed to use the backup.
Since that time I've been sticking with robocopy; the entire tree is identical to the source, and no third-party software whatsoever is needed to access any specific file and without mounting anything. Of course that does nothing for bootable disks and the like, but considering I'm primarily interested in backing up VHD/VHDX files (and not physical disks), I can get away with it.
The entire "disk" is encrypted with VeraCrypt which, in a case like this, is preferable over a file container (.VC files). Since this is a hardware RAID, neither Windows nor VeraCrypt are really aware the underlying disk is actually a RAID (maybe they are, but since this is "supposed" to be transparent, I'm guessing they don't do anything special about it.
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To add to the discussion, here are some thoughts and information:
- Poor throughput could be linked to the RAID5 being either degraded or still being built. I found some Youtube videos showing that (for your model) you would get about max 40 MB/s write speed in such a case, opposed to about 80 MB/s with a healthy array.
- As mentioned by others, these entry level enclosures have pretty low hardware specs and most often do software RAID inside the box. This can seriously impact performance.
- USB 3.0 throughput can reach 5 Gb/s, or 500 MB/s after overhead etc. USB 3.1 can do double that. USB 2 can do about 1/10 of that. So you are getting USB2 speeds at best.
- Have you checked transfer speeds on another PC?
- Finally, your NAS initially came out in 2010, which is a century ago in IT terms.
I run a pair of Asustor NAS with 2.5Gb/s ethernet interfaces. I get 250 MB/s read and write speeds with a simple Windows Explorer copy [^]. These NAS do however have a couple of NVMe SSD cache drives in them. A third NAS with 1 Gb/s and no cache drives gives a solid 100 MB/s. I have yet to test VM perfomance, but the NAS can expose iSCSI volumes so I am expecting to see similar performance from inside a VM.
So old that I did my first coding in octal via switches on a DEC PDP 8
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As part of my analysis, I looked at the manufacturer's web page for the NAS box. It claims that the RAID is done in hardware.
Freedom is the freedom to say that two plus two make four. If that is granted, all else follows.
-- 6079 Smith W.
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I have a WD PR4100 NAS configured to use RAID5 with 8TB WD Red drives. When writing to the NAS over a 1GB/s network, I get speeds of at least 60-100 Mbps. Unless you are writing large amounts of tiny files, I would expect at least that sort of performance out of any NAS.
USB 3 has a maximum transfer rate of 5 Gbps, and USB 2 has a maximum transfer rate of 480 Mbps. Even using USB 2, the transfer rates are very low. I would try each single drive in a different enclosure, if you have one, and then try one of the single drives in the NAS enclosure. This should give you enough information to determine whether it is one of the drives or the NAS that is the bottleneck.
Freedom is the freedom to say that two plus two make four. If that is granted, all else follows.
-- 6079 Smith W.
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Daniel Pfeffer wrote: Unless you are writing large amounts of tiny files, I would expect at least that sort of performance out of any NAS.
So far I've only been trying to backup VM files - so, very few, but rather large files (multiple dozen GBs in size).
Daniel Pfeffer wrote: Even using USB 2, the transfer rates are very low
Agreed, I've been using other single drives using the same USB3 port and connector, and get much better speeds. So I have to rule out this beign stuck in USB 2 mode.
Your idea of testing out each drive separately is a good one. I wonder if I could power down the RAID, take one drive, put it in an enclosure and, without reformating it, run some sort of non-destructive speed test, then put the drive back in the RAID. I'd hate to rebuild it all over again at this point.
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dandy72 wrote: I wonder if I could power down the RAID, take one drive, put it in an enclosure and, without reformating it, run some sort of non-destructive speed test
Given that you want to test WRITE speed I would say no, not unless you can find a non-destructive write test. I don't know of any test program that works like that.
You may also have to take into account the behaviour of the NAS. It may detect that the drive is part of a very degraded RAID-5 set and refuse to mount it. You may have to tell the NAS that this is a JBOD and have it reconfigure the drive before it can be accessed.
Freedom is the freedom to say that two plus two make four. If that is granted, all else follows.
-- 6079 Smith W.
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I know Steve Gibson's Spin-Rite performs non-destructive read/write operations - it'll read what's on a sector and hang onto that data before performing a write test, and then write back what was originally there, regardless of file system, OS, encryption, etc. I suppose that would do it. But I don't think Spin-Rite has anything about reporting read/write speeds. Might still be worth a shot.
Also - strictly speaking - this is a RAID enclosure, not a NAS...
I believe it's supposed to turn on some red LED if it detects any sort of problem, but that's not the case here.
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First, RAID 5 with 8 TB drives is asking for complete, 100% data loss. The reason is that if you have one drive fail, when you replace it the entire RAID set has to be restored and during that restore even a single burp from one of the other three drives will double fault your data store, causing the entire store to corrupt. RAID 5 is also very computation expensive in that the data has to be split up across the drives during writes and then recombined on reads.
Second, if you want performance from large drives in a RAID environment, use RAID 1 or RAID 10. These are striped. Personally, I would use RAID 10 in your case, resulting in 16 TB of resilient storage. RAID 1 and 10 are mirrored so there is no computation involved, just two writes. During read either drive in the pair may be read depending on drive availability.
Finally, veracrypt is a good product, but if your system supports BitLocker at the hyper-v level, use it instead. There is a lot less overhead with BitLocker relative to veracrypt. I don't think this is causing your performance problems, though. I suspect one of your drives is on the way out and the RAID controller is having to do a lot of extra reads and writes to keep that drive responding.
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Very interesting thoughts from someone who obviously has a lot more RAID experience than I do. I appreciate you sharing that.
Are failures during rebuilds so common that RAID admins consider them to be a real concern? I don't question the possibility of having two failures occurring close to each other in time...I'm wondering if you're suggesting that a RAID 5 config exacerbates the likelihood of multiple failures. I suppose all drives are working harder while the whole thing is being rebuilt...
In a way, I'm ok(-ish) with the possible loss - the whole RAID is intended to only act as an additional backup set (not my only backup set). So long as it doesn't take a week to rebuild if I do ever encounter a failure.
And since this is only for backups, I'm not terribly concerned about squeezing every last iota of performance - but again, not sacrificing performance to the extent that I'm seeing right now.
As mentioned elsewhere in this thread, I thought RAID5 was a good compromise between redundancy and capacity. I'm not a huge fan of the thought of pure duplication (eg, losing 50% of total capacity). OTOH, I'd be willing to do it if it guaranteed it brought performance back to where it ought to be. But if it only made things marginally faster, I don't think I'd be in a much better place.
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dandy72 wrote: suggesting that a RAID 5 config exacerbates
IMO, it's the drive count. For RAID 5, it's just a sort of high barrier to entry where it's just not worth doing unless you're using a fairly large number of drives (9+) because fewer drives tends inherently mean the recoverability/performance benefits would be better in a different RAID mode.
You're right though. Something with that enclosure or one of those drives or something about the NAS networking is not right.
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Just a thought, have you tried the enclosure on a USB 2 socket?
So old that I did my first coding in octal via switches on a DEC PDP 8
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I can't say that I have.
But I will definitely try it. Ironic, if a USB2 port turned out to be faster with this RAID enclosure than over USB3 or eSATA (USB2 is faster than what I'm currently seeing, so yes, it would be an improvement...)
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Years ago, I lived in the land of RAID. In my case, I had the need for high throughput for industrial systems. In circa 2000 all we had were spinners, and the fastest were SCSI. So, RAID made sense for higher performance and redundancy. I forget the manufacturer but they were high end and we paid a lot of $$ for these units. Redundant power supplies, controllers, drives, etc. Then one day, one of the controllers failed, and we lost the entire RAID. Seems the controller boards were sort of redundant. As the manager for the data group, it was an interesting conversation with the tech, support and ultimately a VP. It started with "you have to be elephanting kidding me?" Where upon I replaced their product.
Why do I say this? First, RAID helped but tech has passed on. If you are doing this for a science experiment, fine. For day to day, it's just not worth the hassle. Go buy some 4 tb usb drives and move on.
But let's talk about specifications. It is true that USB 2.0 supports UP TO 480 Mbps. USB 3.0 supports UP TO 5.0 Gbps. Note the "UP TO." The interface may support it, but I have yet to find a device that even approaches this transfer rate. I admit I have not tried a RAM disk. I have a fairly high end laptop with USB 3.2 on it. I can plug in a USB 3.2 SSD and copy my VMs to it. The burst speed is actually quite good, but when the cache fills, the transfer rate drops to 10% of the spec rate (I'm ballparking here, it's been a while since I did the test).
So, if you are moving large files - like me - 150GB for a VM via cut/paste, the cache will fill up and you will see perf degrade. This is with modern hardware. Your old spinners? I'd expect worse.
Charlie Gilley
“They who can give up essential liberty to obtain a little temporary safety deserve neither liberty nor safety.” BF, 1759
Has never been more appropriate.
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I had a similar experience decades ago with a RAID controller that failed. RAID sounds great in theory, but when it's the controller that dies...you're no better off, and you now have more data that's unrecoverable than you would had you been using a single, smaller drive...
I reluctantly gave up on the idea for the longest time, concluding that a good RAID just isn't available at consumer prices.
This enclosure was under $200, so I figured why not give it another shot - especially since I had four of these 8TB drives not doing anything anymore.
charlieg wrote: Go buy some 4 tb usb drives and move on.
Actually I have more than enough larger drives already. They're sitting here doing nothing, which is the whole reason I decided to try to put them to some use in a RAID setup.
charlieg wrote: So, if you are moving large files - like me - 150GB for a VM via cut/paste, the cache will fill up and you will see perf degrade
I've definitely seen this. Reading the first couple of GBs with robocopy is fast. Watching Task Manager's memory usage is rather interesting during that time period. Then it flattens out, and performance starts to crawl once it reaches a certain point.
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"concluding that a good RAID just isn't available at consumer prices."
we ended up removing the raid from the system overall, and this was a pure hi-end industrial unit.
Typing this reminds me I need to do backups 
Charlie Gilley
“They who can give up essential liberty to obtain a little temporary safety deserve neither liberty nor safety.” BF, 1759
Has never been more appropriate.
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Just to confirm, the USB3 connection is USB-C? I have a NVME enclosure which had full USB3 speeds in one cable orientation, but if flipped 180 it would be USB2. I would hope it's not something as simple as that. Can't hurt to try. I know that's the whole point of USB-C, however, that doesn't mean everyone handles things correctly
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The docs say the enclosure is USB 3.0 - not 3.1, not USB-C (which, as I understand it, can be faster still).
The cable that came with it is the plain ol', standard USB-A (rectangular) at one end, and USB-B (commonly used for printers) at the other, so I can't get them wrong. The connectors are blue, which suggests USB 3 (and not 2).
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Wordle 1,032 3/6
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Ok, I have had my coffee, so you can all come out now!
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Wordle 1,032 3/6*
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"I have no idea what I did, but I'm taking full credit for it." - ThisOldTony
"Common sense is so rare these days, it should be classified as a super power" - Random T-shirt
AntiTwitter: @DalekDave is now a follower!
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Wordle 1,032 4/6
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(16. April 2024) 4/6
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MessageBox.Show(!string.IsNullOrWhiteSpace(_signature)
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Wordle 1,032 4/6*
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Happiness will never come to those who fail to appreciate what they already have. -Anon
And those who were seen dancing were thought to be insane by those who could not hear the music. -Frederick Nietzsche
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