Slow transfer speed due to SSD cache acceleration

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pokrakam
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Re: Slow transfer speed due to SSD cache acceleration

Post by pokrakam »

Not quite, we do want a write cache because writes to a clean SSD are faster than to HDD. What we do not want is for writes to perform _slower_ than spinning HDDs.
An asynchronous fill of read data is a good idea, but for writes we'd have to consider data consistency, as the SDD also represents the 'definitive' version in case of power failure before it is written to HDD. At least that's my understanding.

I'd be happy with a simple solution to just skip the cache and write straight to HDD when there is no space in the cache.
An automatic clearing mechanism to clear it down to something like 25% free space whenever idle would also solve a majority of the slowdowns.

I can't understand why, if there are several relatively easy ways to achieve at least uncached performance, we are still struggling with this.
elmucki
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Re: Slow transfer speed due to SSD cache acceleration

Post by elmucki »

I have read a lot of post (and this one was by far one of the longest...)
I have a TS1635AX upgraded to 16GB of memory.
I have 2x 1GB M2 SSDs in Raid 1 for Cache Acceleration
I have 3x 12 TB HDD in Raid 5.

I get poor (in my opinion) speeds. I have a 10G network adapter with fiber cable (5ft). I am mainly using it as a home networking solution (movies, music, some light work stuff). I can easily achieve 300-500 MB transfer rates, but i just cant seem to hit 1000MB.

Nothing seems to be able to get me there.
elmucki
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Re: Slow transfer speed due to SSD cache acceleration

Post by elmucki »

forgot to add, i am for from networking savy, just basic knowledge, but being able to reach those speeds seems to be challanging.
Last edited by elmucki on Mon Feb 15, 2021 4:24 am, edited 1 time in total.
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dolbyman
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Re: Slow transfer speed due to SSD cache acceleration

Post by dolbyman »

Neither your SATA cache nor your 3 drives will hit anything close to 10GbE ..so not sure what you are expecting
elmucki
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Re: Slow transfer speed due to SSD cache acceleration

Post by elmucki »

maybe advice on how to achieve it? SATA tops out at what 6GB? I assumed that with a certain set up or configuration it would be doable. I assumed that an SSD cache would speed things up, but doesnt seem to do that.
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dolbyman
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Re: Slow transfer speed due to SSD cache acceleration

Post by dolbyman »

the cache (might) help with random IO ..not with sequential transfers

for maxium sequential, use fast all spinning drives...make sure nothing else runs on the nas as it's very low power (arm)
elmucki
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Re: Slow transfer speed due to SSD cache acceleration

Post by elmucki »

I figured. I am using Ironwolf drives (https://www.amazon.com/gp/product/B08L9 ... UTF8&psc=1)
I was just hoping that there would be a way to "accelerate" transfers (especially larger ones). I mean i can copy a DVD (7GB) in a few seconds, so i am not complaining.
Upgrading CPU is not doable from what i noticed. I mainly went with this NAS for the value... 16 bays for under $1400. I mean, c'mon, steal of a deal.
But i have noticed that even other NAS units which are 10G capable, rarely see those speeds.

That search led me to this post and there doesnt seem to be an answer aside "contact support"
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dolbyman
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Re: Slow transfer speed due to SSD cache acceleration

Post by dolbyman »

The cpu cannot be changed as it is a permanently cell phone type one ..hence the low price.

That is not to say that this NAS should work fine for plain data storage
elmucki
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Re: Slow transfer speed due to SSD cache acceleration

Post by elmucki »

I love this NAS. But I'm just wondering, is it possible to achieve 10G speeds, and if so, how and with what hardware and settings.
P3R
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Re: Slow transfer speed due to SSD cache acceleration

Post by P3R »

elmucki wrote: Mon Feb 15, 2021 6:27 pm But I'm just wondering, is it possible to achieve 10G speeds, and if so, how and with what hardware and settings.
Adding more disks to the RAID 5 will definitely increase performance up to a point but it probably won't be able to reach full 10 GbE speed. Another problem is that it's recommended to migrate to RAID 6 when having more than 4 large disks in the RAID and that will again set your performance back due to the limited CPU.

I'm not sure but it may be possible to saturate the network with a static volume on 6, 7 or 8 disks in RAID 0 (and possibly limit all other services and apps) but that's a very odd and risky configuration. TS-1635AX is a large capacity workhorse but it simply isn't a good hardware to use if maximum performance is the goal.
RAID have never ever been a replacement for backups. Without backups on a different system (preferably placed at another site), you will eventually lose data!

A non-RAID configuration (including RAID 0, which isn't really RAID) with a backup on a separate media protects your data far better than any RAID-volume without backup.

All data storage consists of both the primary storage and the backups. It's your money and your data, spend the storage budget wisely or pay with your data!
Bob Zelin
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Re: Slow transfer speed due to SSD cache acceleration

Post by Bob Zelin »

Hello Elmucki -
you say "I love this NAS". I love QNAP, but I do not love the TS-1635, TS-1635X or TS-1635AX. QNAP makes lots of great products. The TS-1635ax is not one of them. You will not get 1000 MB/sec on a TS-1635ax. Had you spent $1500 more and purchased a TS-1685 (and today in 2021, you would have purchased the TVS-h1688X), you would be easily getting your 1000 MB/sec. But when you have a crappy CPU in the system, you get poor performance.

Let's take some other models. People look at the TVS-872XT 8 bay, and the new TVS-h1288X, and say "wow - I want those - but I can get another QNAP - the TS-832PX that has 10G ports for SO MUCH CHEAPER". Well - the TS-832PX is junk (like like the TS-831X was junk) and the TVS-872XT, the TVS-h1288X, and even the OLD OLD TVS-871T were great (and the TVS-1282T was great) - all 8 bays, all with 10G, all great. The TS-832X, and anything that is Annapurna based is complete garbage.

A Dodge Challenger is not a Ferrari - but a Dodge Challenger can at least perform. A Hundai, while it has its uses to get to work, cannot compete with a Ferrari or a Dodge Challenger - even though they all have 4 wheels, and run on regular gasoline.

SO - what can you do to make your TS-1635ax run as fast as the more expensive QNAP systems ? Nothing. Sell it, save your money, and buy the proper QNAP.
Bob Zelin
Bob Zelin / Rescue 1, Inc.
http://www.bobzelin.com
elmucki
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Re: Slow transfer speed due to SSD cache acceleration

Post by elmucki »

QNAP TVS-h1688X-W1250-32G 16-Bay Hybrid NAS is a beast looking at the specs.... and price. I bet definitely worth it, just too much for me.... maybe in 10 years
Pfeffernuss
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Re: Slow transfer speed due to SSD cache acceleration

Post by Pfeffernuss »

Bob Zelin wrote: Tue Feb 16, 2021 10:03 am Let's take some other models. People look at the TVS-872XT 8 bay, and the new TVS-h1288X, and say "wow - I want those - but I can get another QNAP - the TS-832PX that has 10G ports for SO MUCH CHEAPER". Well - the TS-832PX is junk (like like the TS-831X was junk) and the TVS-872XT, the TVS-h1288X, and even the OLD OLD TVS-871T were great (and the TVS-1282T was great) - all 8 bays, all with 10G, all great. The TS-832X, and anything that is Annapurna based is complete garbage.
I have one of those garbage products, the 932px. Would I have rather had a 1282? Well yes. But that NAS is 4x (four times) as expensive, enclosure only. Completely unreachable for me and probably a lot of other people as well.

In the NAS I put 5 8TB hard discs for storage and 4 SSD's running as QTier (which is also regarded as a useless feature in these threads).

However, stuff goes to the NAS at around 700/800MB per second and retrieving it, while a lot slower (appr. 370MB) , is easily sufficient for my usage (streaming 4K media) and photo viewing. I only wanted a 10GBe NAS to store large (40-70GB) movies without having to wait for ages and occasional other content.

So, although a bottom of the range crap abysmal utter garbage products it probably is, I'm quite happy with it.

YMMV.
holger_kuehn
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Re: Slow transfer speed due to SSD cache acceleration

Post by holger_kuehn »

Pfeffernuss wrote: Wed Feb 17, 2021 8:54 pm
Bob Zelin wrote: Tue Feb 16, 2021 10:03 am Let's take some other models. ...
I have one of those garbage products, .... , I'm quite happy with it.
I've to agree to this, I'm quite happy with the TS1635AX, using it as Mediastorage and Plex-Server. As most of the Network is still 1GB, the read and write performance of around 500 MB/s is more then enough to serve the six workstations / mediaplayers at the same time.

I've not done any videoediting with it, so I'll not judge it there. But it all depends on the use case for it ...
NAS (production): TS-1635AX FW: QTS 5.1.4.2596 build 20231128
NAS (backup): TS-1635AX FW: QTS 5.1.4.2596 build 20231128
QTS (SSD): [RAID-1] 2 x 2TB Samsung Evo 860 M.2-Sata
Data (QTier): [RAID-6] 4 x 4TB Samsung 870 QVO Sata
Data (HDD): [RAID-6] 7 x 18TB Exos
RAM: 8 GB (QNAP shipped)
UPS: CyberPower CP900EPFCLCD
BACKUP: 10x4TB WD Red using a USB 3.0 Dock
Usage: SMB with rclone (encrypted)

NAS: TS-873U-RP FW: QTS 5.1.4.2596 build 20231128
Data (SSD): [RAID-10] 4 x 1TB Samsung Evo 860 Sata
RAM: 8 GB (QNAP shipped)
UPS: CyberPower PR2200ELCDRT2U
BACKUP: 4TB Synology DS214 FW: DSM 7.0.41890
Usage: SMB, Backup Domain Controller
craig.williams
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Re: Slow transfer speed due to SSD cache acceleration

Post by craig.williams »

I have had the same experience.
As soon as it fills up it slows down and seems to work overtime. Ran the same tests same results.
There should be a job that could kick in when it reaches a water mark like (90% full) stop cache and start clearing.
Would say the same thing about QBoost. When processes slow down cleanup! In my case I would say when Microsoft Networking drops below 1% and Memory is easily recoverable then clean it up. You could set it on a timer, check every 10 minutes. Just hit mine and went from 289MB free to 20GBfree.


The same is really true about using it as write cache, as soon as the system gets below 5% of usage get those files off cache. There is no reason to have them there if it is ONLY write cache.

If there are read only cache that is trickier and requires more overhead but you could easily reserve space on the drive ( lets say 20%) and when that mark gets hit start scrubbing off files.

Cache works best if it is EMPTY. It slows down as it fills and that is of no value to us as cache.

I have to second the tech from QNAP about switching the style of the cache and setting a watermark for the size of the files to store in cache. I store 100s of millions of files across 100T of space and it seems to work better than the other but both have their issues. Remember that a fast RAID 5 or 6 is 3 times the speed of spindle already so the biggest hit you get is in writing to the RAID which is still at rated speed of spindle. Read cache just is not necessary in the case of a 5/6 raid. Write cache helps but not very well, I to have turned my cache off and see very little difference. Perhaps the newer OS that QNap is installing will help as it is self healing and should have some of these features built in. Still like the product so far it is just flakey from time to time.

We use RAID 6 for live data and 5 for backups. If I had my way now that drives are cheaper I would go RAID 10 for live data and raid 5 for backups. Next upgrade.
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