F5 422 nas is slower ssd cache on.

RAID, Volume, storage pool, hard drive, USB, SSD cache and iSCSI LUN
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joprysko
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Joined: 10 Aug 2021, 01:42

F5 422 nas is slower ssd cache on.

Post by joprysko »

Not really sure whats going on. I just got this NAS a few days ago.

The nas is connected to a 10GbE network to a 10GbE pc.

I am using 4 x 4tb seagate enterprise drives. I originally had then in raid 5. I added a ssd in slot 5 as a cache. The transfer speeds up and down seemed to slow. No faster than 180mb/s

I redid the raid in raid 0 with no ssd cache to see if maybe it was a hardware issue. Transfer speeds up and down over 500mb/s transfering a 2.5gig video file back and forth.

I added a samsung 1tb desktop ssd as cache and tranfer rate dropped to no faster than 180mb/s again. Thinking it may be an ssd issue (even though it tested fine on desktop) I purchased a 500 gb western digital red. The results where exactly the same.

So I am at a loss as to what the issue may be.


On a side note I discovered that every time you add or remove ssd cache it wiped out the contents of the plex user folder. Possibly all folders but i had nothing in the others to see.
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TMSupport
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Re: F5 422 nas is slower ssd cache on.

Post by TMSupport »

Hi!
After adding SSD cache, it is possible to slow down the copy speed. Because the data is directly copied to the hard disk without the SSD cache; if the SSD cache is added, the data is written to the SSD first, and then to the hard disk.
Using SSD cach to improve speed is mainly for files that are frequently read and written, such as database files. There is no acceleration effect for copying some files.

In addition, every time a SSD cache is added or deleted, the TNAS device needs to be restarted. It is impossible to delete related content in PLEX.
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joprysko
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Re: F5 422 nas is slower ssd cache on.

Post by joprysko »

TMSupport wrote: 10 Aug 2021, 15:37 Hi!
After adding SSD cache, it is possible to slow down the copy speed. Because the data is directly copied to the hard disk without the SSD cache; if the SSD cache is added, the data is written to the SSD first, and then to the hard disk.
Using SSD cache to improve speed is mainly for files that are frequently read and written, such as database files. There is no acceleration effect for copying some files.
I don't know if I buy this explanation. Going from over 500MB's to 180MBs in both read and write speed because of adding SSD cache seems extremely counter productive to the point of why would you do it at all. I have done many searches prior to writing this up and I have never seen people saying they dramatically loose performance from adding a SSD Cache. other than on other TNAS posts. I understand the cache is designed for frequently used files, but I would expect at least close to the same transfer rate to the raid as I would with out the cache.

TMSupport wrote: 10 Aug 2021, 15:37 In addition, every time a SSD cache is added or deleted, the TNAS device needs to be restarted. It is impossible to delete related content in PLEX.
On this note I would highly suggest you test this. It is not only is it possible, it is certain and will happen every single time.

To replicate it simply install and set up plex, I used transferred an existing Plex database with over 4GB in Plex Library Files. The location of these files is stored in "users/plex/library" once plex is set up, configured and tested as working, simply add or remove SSD cache. After it reboots the user directory for plex will be a fresh install and no longer configured. All the library files will be default ones, in other words empty of the database and images.
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TMSupport
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Re: F5 422 nas is slower ssd cache on.

Post by TMSupport »

Sorry for the inconvenience, we will verify it soon.
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joprysko
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Re: F5 422 nas is slower ssd cache on.

Post by joprysko »

Here is an example of the real world transfer speeds moving 7GB in files to an M.2 Nvme desktop drive from the NAS and then back. Higher speeds are with out Cache.
Untitled-2.jpg


Additionally here is the before and after Plex user directory.
Untitled-3.jpg
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TMroy
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Re: F5 422 nas is slower ssd cache on.

Post by TMroy »

To contact our team, please send email to following addresses, remember to replace (at) with @:
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joprysko
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Re: F5 422 nas is slower ssd cache on.

Post by joprysko »

Not sure what you want me to take away from this thread. I actually reviewed it looking for answers prior to posting this thread. It does not appear to come to a conclusion other than the Physical disks may have been faulty or relabeled damaged disks. They also experienced crashing, I have had no such issue.

The drives I am using are 4 X Seagate Constellation ES.3 ST4000NM0035 4TB 7200RPM 128MB Cache.
Originally placed in Raid 5 then changed to Raid 0 for testing after I noticed SSD the issue in Raid 5.
The Original SSD drive I tested with is a Samsung 840 EVO 1TB, I replaced it with a Western Digital 500GB WD Red SA500 but the issue remained the same.

I did bad block scans on all physical drives prior to copying any data to the raid and everything came up good. Drive S.M.A.R.T. shows everything as OK.
I have been having no issues with the NAS at all other than when adding SSD Cache.

Currently there is over 1TB of data that has been copied to the NAS from various sources and with out issue.

What would you suggest?
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joprysko
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Re: F5 422 nas is slower ssd cache on.

Post by joprysko »

After re-reviewing the thread you linked, his solution was to replace the NAS with one of your competitors models. I mean, I could do that as well if there is no solution to the issue, but seems like that should not be the answer.
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joprysko
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Re: F5 422 nas is slower ssd cache on.

Post by joprysko »

Ok here is what I discovered.

I removed the raid 5 array and reinitialized the NAS with only the Western Digital 500GB WD Red SA500 SSD drive in.

Here is the problem:

The SSD drives (I tried both) do no function correctly in the NAS. For example:

This image shows the speed of the WD red SSD when placed in a PC.
WD Red PC.jpg
And this shows the speed when it is placed in the NAS as a single SSD drive.
WD Red Nas.jpg
As you can see these results would absolutely destroy read and write speeds of any raid rather than enhance them. Both SSD drives function as expected when installed into a Windows based PC so my guess is it could be an OS based issue with ToS or a hardware issue with the unit.
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TMSupport
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Re: F5 422 nas is slower ssd cache on.

Post by TMSupport »

Hi!
We did a test on F5-422 (TOS 4.2.15), using 4 x 10tb seagate enterprise drives to form raid0, and adding a 512G HIKVISION SSD as a cache, transfering 7GB files.
Before and after adding SSD, the write speed has been maintained at 300+MB/S.
Before adding SSD, the read speed was 300+MB/s, and after adding it, it dropped to 50+MB/s.
Another test on F5-422 (TOS 4.2.15), using 3x 512G HIKVISION SSD to form raid0, and adding a 512G HIKVISION SSD as a cache,transfer 7GB files.
Before and after adding SSD, the write speed has been maintained at 400+MB/S, and the read speed has been maintained at 300+MB/S.
It may be related to the compatibility of SSD, we need to do more related tests.

As for the plex issue, after verification, we found that adding SSD will delete the file in Library folder, but it will not be deleted after removal. We are modifying the related problem.
To contact our team, please send email to following addresses, remember to replace (at) with @
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