Slow transfer speed due to SSD cache acceleration

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mman3222

Re: Slow transfer speed due to SSD cache acceleration

Post by mman3222 » Fri Sep 11, 2020 11:02 pm

P3R wrote:
Fri Sep 11, 2020 3:37 pm
mman3222 wrote:
Fri Sep 11, 2020 3:01 pm
Lets say I have file "123.mkv" in NVMeDrive\Movies. Will it copy to my regular store or MOVE/cut it to regular storage? When Syncback runs at night, it moves the files so then my cache drive is 100% empty again.
Ah, okay. It's not really synchronizations, it's moving data.

HBS can't do moves, only backups and syncs. That's very easy to work around though as piggy-backed to the sync job you could have a job that sync an empty folder to the SSD folder and thereby delete all data on it. In addition, that would be a completely safe transfer of the data. I don't know if Syncback actually do a sync plus delete behind the scenes or if it really use the more risky approach of moving? If the latter, that would be another disadvantage with Syncback.

If you're not familiar with HBS, how do you backup the data on the NAS? Do you use Synback for that as well?
It's just easier for me to stick with Syncback then. I only have 0 - 600GB MAX in a night it needs to move. However, the average is probably 50 - 100GB.

I use Google Drive with Stablebit to backup my data. And you're correct. I use Syncback for that too. Once a day it backs up. Stablebit tricks Google Drive to making it a "local" hard drive on my computer. It's encrypted, and Syncback backs all my stuff up flawlessly. I've been using this method for around 2 years now.

P3R
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Re: Slow transfer speed due to SSD cache acceleration

Post by P3R » Sat Sep 12, 2020 12:35 am

mman3222 wrote:
Fri Sep 11, 2020 11:02 pm
I use Google Drive with Stablebit to backup my data. And you're correct. I use Syncback for that too. Once a day it backs up. Stablebit tricks Google Drive to making it a "local" hard drive on my computer. It's encrypted, and Syncback backs all my stuff up flawlessly. I've been using this method for around 2 years now.
HBS can backup to Google drive as well, including doing client-side encryption, but if what you have work and you're happy with it I understand that you don't want to change as HBS will no doubt require some learning time.

I just wanted to inform that a good NAS-integrated backup/sync solution existed for those that wasn't aware. I do agree that Syncback is a nice Windows backup software. :)
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!

pokrakam
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Re: Slow transfer speed due to SSD cache acceleration

Post by pokrakam » Sat Sep 12, 2020 11:09 pm

FWIW, I have had numerous issues with HBS as it does not play nicely with S3-compatible storage. So I use Arq backup on a Mac to backup my NAS.

HiTach
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Re: Slow transfer speed due to SSD cache acceleration

Post by HiTach » Wed Sep 23, 2020 5:00 am

So today I checked my W/R speeds and was very surprised. :S :-0 :DD
This 872XT system has been up for 12 days. I have not flushed the cache since.
See images for surprising speeds - 1202MB/s Write 1862MB/s Read
Repeatable over several tests +/- 100 MB/s.
Most system specs in signature, using Mellanox MCX313A single port 40GB/s card on host pc but still MCX314A dual port 40GB/s card on NAS.
I use the second NAS 40GB/s port with adapters to provide 10Gbe on 10-BaseT.

I also confirmed by transfer multiple 30GB movie files at 1.3GB/s to 1.9GB/s with Windows file copy.

I have no idea what, but for months I have been lucky to see 700MB/s W/R and sometimes as low as 500 or even 400 MB/s.

I'll keep track over the coming days and hope it's sustained. I am up to date on QTS 4.4.3.1421.
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Workstation DAS/NAS: TVS-872X
8x10TB WD Gold RAID6 54TB static volume
2x1TB Samsung 970 EVO plus R/W RAID1 cache w/EK WB M.2 heatsinks + 2x NB 12-P fans
1x40Gbe Mellanox DAS network connection, 1x10Gbe QXG-10G1T for local 10gbe virtual switch
Backup NAS: TVS-872XT
8x10TB WD Gold RAID6 54TB Thick volume w/snapshots
1x40Gbe Qnap Thunderbolt 3 card, 1x10Gbe QXG-10G1T for local 10gbe virtual switch
LAN switch 10Gbe(2)/1Gbe(8) NETGEAR Nighthawk SX10 (GS810EMX)

mman3222

Re: Slow transfer speed due to SSD cache acceleration

Post by mman3222 » Wed Sep 23, 2020 6:40 am

Those speeds are normal for me with my TS-672XT. I have a Samsung 1TB M.2 970 EVO SSD that I use for cache and I get 1.15GB/sec over a mixture of cat 5e / cat 6 cables.

I'm surprised you were getting such slow speeds prior to this.

dnavas
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Re: Slow transfer speed due to SSD cache acceleration

Post by dnavas » Sun Oct 25, 2020 2:36 pm

Hmm, technically I think QNAP is right?? -- eviction from a cache typically occurs on cache-full. It could very well be that the cache is being written through to the drive (although, if you're spending a lot of time waiting for a flush, it appears not, and that DOES appear to be counter to their docs), but that doesn't imply it should be evicted from the cache. The cache will definitely fill up and absent some kind of timeout mechanism....
What most of us actually want, I think, is a large write buffer (not a cache) and a large read cache with asynchronous fill (don't block reads to populate the cache).
Does that sound right, or am I misunderstanding this thread?

pokrakam
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Re: Slow transfer speed due to SSD cache acceleration

Post by pokrakam » Sun Oct 25, 2020 7:13 pm

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 » Mon Feb 15, 2021 4:15 am

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 » Mon Feb 15, 2021 4:22 am

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 » Mon Feb 15, 2021 4:22 am

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 » Mon Feb 15, 2021 4:27 am

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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Re: Slow transfer speed due to SSD cache acceleration

Post by dolbyman » Mon Feb 15, 2021 4:57 am

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)

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Re: Slow transfer speed due to SSD cache acceleration

Post by elmucki » Mon Feb 15, 2021 5:10 am

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 » Mon Feb 15, 2021 7:58 am

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

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Re: Slow transfer speed due to SSD cache acceleration

Post by elmucki » Mon Feb 15, 2021 6:27 pm

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.

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