Slow transfer speed due to SSD cache acceleration

[vikino]

I've been watching it too, but im little affraid of going to Qtier on production system as it is unreversible... Cache is just by clicking disabled, but disabling Qtier is to reinstall everything...

[storageman]

Sorry that my 1st post here is a 'bad' one:
I second that slow down behaviour with the QTS 4.3.4 Beta2 also...

The Hardware-Information shows only (PCIe) for the QM2 board.
The I/O leds on the QM2 board aren't ligthen up on NW transfers
This board was just newly installed with two Intel 600P (I know - they are the slower ones)

System: TS-531X-4G + 5x WD 3TB + 2x 128GB NVMe SSD in QM2 card for cache

Which QM2 card?
For NVMe this?
http://shop.qnap.com/index.php?route=pr ... uct_id=214
Don't see those disks as compatible.

[Trexx]

Sorry that my 1st post here is a 'bad' one:
I second that slow down behaviour with the QTS 4.3.4 Beta2 also...

The Hardware-Information shows only (PCIe) for the QM2 board.
The I/O leds on the QM2 board aren't ligthen up on NW transfers
This board was just newly installed with two Intel 600P (I know - they are the slower ones)

System: TS-531X-4G + 5x WD 3TB + 2x 128GB NVMe SSD in QM2 card for cache

Which QM2 card?
For NVMe this?
http://shop.qnap.com/index.php?route=pr ... uct_id=214
Don't see those disks as compatible.

I would also question whether the ARM processor in the x31 really has the horsepower to even leverage NVMe throughput in the first place.

I know Bob Zelin has posted about seeing MUCH lower storage throughput over 10GbE to spinning disk in the Arm Series boxes (TS-1635, x31X, etc.) vs. similarly configured Intel boxes.

[storageman]

Cards are on compat list. Expectations start from there.

[Trexx]

Cards are on compat list. Expectations start from there.

True... but compatible and optimal are 2 different things

[BryceWilkins]

It has been three months since the last update here and now QNAP OS v4.3.4 is out of beta for a while (currently 4.3.4.0537 build 20180331), so I wonder if there is anything new to report on the performance issue (write cache with RAID 1 setup, and writing large files).

Has the SSD cache acceleration improved? Are people making use of QTier 2.0 and find it works better for them?

I've just bought the TS-877-1700 so I'm mostly looking at Trexx's posts here and considering my options; I wonder if Trexx is still using the SSD cache or only QTier (2.0), and reasons for the change?

I didn't buy any M.2 or 2.5" SSDs yet so it's still an open decision what I will do. I don't have 10GB local network yet so cache is probably not going to have any impact for me (the only consideration was for virtual machine, but I could put that directly on SSD).

In any case, would be good to hear any update on the issues discussed in this thread.

[BryceWilkins]

This probably isn't the exact right place, but since I can't send private message on the forum just want to shout out to Trexx and jds580s for all their awesome posts on these forums --- you guys rock for going to lengths to clearly explain the advanced topics including Qtier 1.x/2.x, SSD cache, and "system volume" (meaning QNAP QTS OS files/apps/qpkg/shared folders), and overall always informative information. I've learned a lot from reading your replies, and even I search through all your posts to find answers my questions!

Also, excellent job with the signatures listing your hardware and drive configurations. I didn't realize until now how helpful that info was in identifying experienced users with likely thoughtful/researched configurations of HDDs/SSDs/NVMe/etc, that can be helpful to others. Indeed it helped me arrive at a configuration for my own use.

I will have to update my signature when my new hardware is here and running -- it's arriving tomorrow! I bought TS-877-1700, 2x Samsung M.2 SATA 860 EVO 500GB (RAID 1) for "system volume", WD Red Pro drives for main volume (RAID 5), and WD Purple for surveillance (single volume; non-RAID). I'll leave the 2.5" SSD drives unpopulated for now. Later I will add more RAM (when it is cheap again!) and eventually QM2-2P10G1T for M.2 NVMe RAID-1 cache of the main (HDD) volume, and 10GbE to offload to the LAN once my network is upgraded. It's pretty cool to have NVMe and 10GbE on the same expansion card!

I decided to try for as simple approach as possible -- I will not use Qtier 2.0 for the moment (since it can't be easily "undone"), and also not try SSD cache acceleration, which seems pointless for my limited GbE LAN and that I will use SSDs for the "system volume", on which I can put VM and similar things.

Although not important immediately, one question comes to mind: once I eventually add the NVMe RAID-1 cache, can it cache both the "system volume" (running on SSDs) and the main (HDD) volume at the same time? The benefit is mainly for the later, but I just wonder if the cache must be allocated entirely to one array.

Thanks again guys, and carry on folks!

[Trexx]

; I wonder if Trexx is still using the SSD cache or only QTier (2.0), and reasons for the change?

I didn't buy any M.2 or 2.5" SSDs yet so it's still an open decision what I will do. I don't have 10GB local network yet so cache is probably not going to have any impact for me (the only consideration was for virtual machine, but I could put that directly on SSD).

In any case, would be good to hear any update on the issues discussed in this thread.

I am only running QTier 2.0 right now as it both improves frequently accessed data (hot blocks) plus also has some "Cache Acceleration" benefits as well for certain burst patterns.

I don't have 10GbE yet, but with upcoming house move may get to add that that capability (will have to wait and see).

[Trexx]

This probably isn't the exact right place, but since I can't send private message on the forum just want to shout out to Trexx and jds580s for all their awesome posts on these forums --- you guys rock for going to lengths to clearly explain the advanced topics including Qtier 1.x/2.x, SSD cache, and "system volume" (meaning QNAP QTS OS files/apps/qpkg/shared folders), and overall always informative information. I've learned a lot from reading your replies, and even I search through all your posts to find answers my questions!

Also, excellent job with the signatures listing your hardware and drive configurations. I didn't realize until now how helpful that info was in identifying experienced users with likely thoughtful/researched configurations of HDDs/SSDs/NVMe/etc, that can be helpful to others. Indeed it helped me arrive at a configuration for my own use.

I will have to update my signature when my new hardware is here and running -- it's arriving tomorrow! I bought TS-877-1700, 2x Samsung M.2 SATA 860 EVO 500GB (RAID 1) for "system volume", WD Red Pro drives for main volume (RAID 5), and WD Purple for surveillance (single volume; non-RAID). I'll leave the 2.5" SSD drives unpopulated for now. Later I will add more RAM (when it is cheap again!) and eventually QM2-2P10G1T for M.2 NVMe RAID-1 cache of the main (HDD) volume, and 10GbE to offload to the LAN once my network is upgraded. It's pretty cool to have NVMe and 10GbE on the same expansion card!

I decided to try for as simple approach as possible -- I will not use Qtier 2.0 for the moment (since it can't be easily "undone"), and also not try SSD cache acceleration, which seems pointless for my limited GbE LAN and that I will use SSDs for the "system volume", on which I can put VM and similar things.

Although not important immediately, one question comes to mind: once I eventually add the NVMe RAID-1 cache, can it cache both the "system volume" (running on SSDs) and the main (HDD) volume at the same time? The benefit is mainly for the later, but I just wonder if the cache must be allocated entirely to one array.

Thanks again guys, and carry on folks!

Thanks Bryce for the kind words.

As for your config, I wouldn't recommend doing single PURPLE drive, and just add another WD RED Pro for your surveillance needs. You will get much more benefit from overall (faster performance, better space usage, etc.).

As for NVMe, don't go with the QM2 card if you are looking for performance as it is only PCIe 2.x capable. Use the new PCIe 3.x based SSD cards that were announced and then one of the new/existing 10GbE cards with it.
http://files.qnap.com/news/pressresourc ... 321_v2.pdf
http://files.qnap.com/news/pressresourc ... 180201.pdf

I also wouldn't use it for caching, use it for creating a high-performance volume for VM's, etc. that can benefit from it.

[BryceWilkins]

; I wonder if Trexx is still using the SSD cache or only QTier (2.0), and reasons for the change?

I didn't buy any M.2 or 2.5" SSDs yet so it's still an open decision what I will do. I don't have 10GB local network yet so cache is probably not going to have any impact for me (the only consideration was for virtual machine, but I could put that directly on SSD).

In any case, would be good to hear any update on the issues discussed in this thread.

I am only running QTier 2.0 right now as it both improves frequently accessed data (hot blocks) plus also has some "Cache Acceleration" benefits as well for certain burst patterns.

I don't have 10GbE yet, but with upcoming house move may get to add that that capability (will have to wait and see).

Thanks for update on QTier 2.0, Trexx! That's excellent news to hear it is working well. I will search for thread dedicated to that topic. It would be excellent to know how the "cache acceleration" part works in comparison to the traditional "SSD Cache Acceleration" that has been the focus of this thread. I guess the latter is still an option in QTS 4.3.4...but perhaps still with problems...

I hope sometime that SSD Cache Acceleration can be fixed -- it has advantage of being easy to "trial" if it works well for particular user.

[Trexx]

Thanks for update on QTier 2.0, Trexx! That's excellent news to hear it is working well. I will search for thread dedicated to that topic. It would be excellent to know how the "cache acceleration" part works in comparison to the traditional "SSD Cache Acceleration" that has been the focus of this thread. I guess the latter is still an option in QTS 4.3.4...but perhaps still with problems...

I hope sometime that SSD Cache Acceleration can be fixed -- it has advantage of being easy to "trial" if it works well for particular user.

See the QM2 deck I gave you a link for as they do talk some about QTier2 and the Cache Acceleration built into it vs. SSD Cache Acceleration. Short version, Cache Acceleration really is the biggest benefit for Randon I/O behavior and not really for Sequential access. In fact with SATA SSD's, you can actually have slower cache performance with say a 2-drive raid-1 setup vs. say 6-8 decent NAS rated HDDs on sequential performance.

[BryceWilkins]

Thanks Bryce for the kind words.

As for your config, I wouldn't recommend doing single PURPLE drive, and just add another WD RED Pro for your surveillance needs. You will get much more benefit from overall (faster performance, better space usage, etc.).

As for NVMe, don't go with the QM2 card if you are looking for performance as it is only PCIe 2.x capable. Use the new PCIe 3.x based SSD cards that were announced and then one of the new/existing 10GbE cards with it.
http://files.qnap.com/news/pressresourc ... 321_v2.pdf
http://files.qnap.com/news/pressresourc ... 180201.pdf

I also wouldn't use it for caching, use it for creating a high-performance volume for VM's, etc. that can benefit from it.

See the QM2 deck I gave you a link for as they do talk some about QTier2 and the Cache Acceleration built into it vs. SSD Cache Acceleration. Short version, Cache Acceleration really is the biggest benefit for Randon I/O behavior and not really for Sequential access. In fact with SATA SSD's, you can actually have slower cache performance with say a 2-drive raid-1 setup vs. say 6-8 decent NAS rated HDDs on sequential performance.

Great info! Thanks, Trexx. Excellent links to those documents! There is a wealth of information in the PDF presentations...but how does one find them? I tried browsing the /datasheet directory but got "access denied" -- do you know where these PDFs are linked from?

Certainly I would get one of the new PCIe 3.x cards that combine two SSD NVMe and 10GbE port -- but I've got no application for that level of performance currently. Certainly I could consider to put VMs on those. I must add more RAM first...but that is very expensive right now...so I wait...

Overall it seems the cache acceleration may not be very applicable in my use case which will be mostly sequential IO: data/media storage and retrieval. I can see that QTier 2.0 would be more benefit as it automatically moves the more frequently retrieved files to faster tier of storage.

Hoping to get my gear set up soon!

[Trexx]

Great info! Thanks, Trexx. Excellent links to those documents! There is a wealth of information in the PDF presentations...but how does one find them? I tried browsing the /datasheet directory but got "access denied" -- do you know where these PDFs are linked from?

See the link for QTS Presentations in my signature. Has links to upcoming video/slides as well as previous presentations.

[dolbyman]

do QTIER instead

https://www.qnap.com/solution/qtier-auto-tiering/en/

[vikino]

How to say that in short...with last firmware cache seems to be slightly better...In RAID 10 config im getting 800MB/s read and 450MB/s if cache is flushed and clean and 230MB/s write if cache is full...