What m.2 capacity to buy to store Apps, initial shared folder

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jang430
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What m.2 capacity to buy to store Apps, initial shared folder

Post by jang430 »

I intend to get the TS-873A, 8 bay, with 2 m.2 slots onboard. The m.2 slots are PCIe 3.0 x1. I currently have 5 8TB Exos drives, and will use all of them on the bays. I intend to use Raid Z1. I currently don't have any SATA SSDs for storage yet. I read from QuTS hero page the following info:

Tiered storage configuration for a QuTS hero NAS
Step 1: System Drive & Default Shared Folders
The first Storage Pool you create is where the system drive, default shared folders, and apps are stored. In this step, it is recommended to create an SSD RAID with at least two SSDs to attain optimal system performance and efficient app metadata management. (With an all-HDD configuration, the first Storage Pool is also where the system drive and default shared folders are stored.)

I would still like to have caching enabled, so is it better to have your first Storage Pool in m.2 slots onboard, or SATA SSDs on the bays? What would be a recommended RAID setup to install the System Drive, Default Shared folders, and Apps if I were to get 2 SSDs only? RAID 1?
P3R
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Re: What m.2 capacity to buy to store Apps, initial shared folder

Post by P3R »

jang430 wrote: Sun Jun 27, 2021 2:42 pm I currently have 5 8TB Exos drives, and will use all of them on the bays.
Please be aware that you won't be able to add disks later to the RAID Z1 with ZFS so maybe you want to consider geting 6*8 TB. With 2 drive bays used for SATA SSDs you'll otherwise end up with a free drive bay that will be hard for you to use in the future.
I would still like to have caching enabled, so is it better to have your first Storage Pool in m.2 slots onboard, or SATA SSDs on the bays?
SATA SSDs. They're fast enough for the system pool and the M.2 speed will be better used for caching. As for size I would recommend at least 450 GB with QTS. I would assume the same apply to QuTS but I'm not sure.
What would be a recommended RAID setup to install the System Drive, Default Shared folders, and Apps if I were to get 2 SSDs only? RAID 1?
Yes always RAID 1 with two SSDs.
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!
jang430
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Re: What m.2 capacity to buy to store Apps, initial shared folder

Post by jang430 »

P3R wrote: Sun Jun 27, 2021 4:36 pm
jang430 wrote: Sun Jun 27, 2021 2:42 pm I currently have 5 8TB Exos drives, and will use all of them on the bays.
Please be aware that you won't be able to add disks later to the RAID Z1 with ZFS so maybe you want to consider geting 6*8 TB. With 2 drive bays used for SATA SSDs you'll otherwise end up with a free drive bay that will be hard for you to use in the future.
Just read up on ZFS from Arstechnica website. Wouldn't the 5x 8 TBs in my original statement, in Raid Z1, be a vdev? Wouldn't it be possible to add another vdev later in the future, composed of 3 drives set to RAID Z1, and add it to the zpool? (Just a thought, either all of the additional 3 drives (RAID Z1) in the new vdev be 8 TBs, or 10 TBs? Asking this question just to learn more about how to add vdev to the Zpool, though most likely I'll be following your instructions). If I can add new vdevs such as 3x8 TB or 3x10TB in the future, I don't have to spend a lot up front.

Isn't adding 2 Sata SSDs to the remaining 2 bays (assuming I started with 6) adding Vdevs to the Zpool?
I would still like to have caching enabled, so is it better to have your first Storage Pool in m.2 slots onboard, or SATA SSDs on the bays?
P3R wrote: Sun Jun 27, 2021 4:36 pmSATA SSDs. They're fast enough for the system pool and the M.2 speed will be better used for caching. As for size I would recommend at least 450 GB with QTS. I would assume the same apply to QuTS but I'm not sure.
Having the 2 SATA SSDs in the last 2 bays in RAID 1 is extravagant :D Though I understand there might be no other way. I really cannot find any documentation as to how to determine the right size to use as cache.
What would be a recommended RAID setup to install the System Drive, Default Shared folders, and Apps if I were to get 2 SSDs only? RAID 1?
P3R wrote: Sun Jun 27, 2021 4:36 pmYes always RAID 1 with two SSDs.
So does it mean I have to get 2 SATA SSDs first, to set it up at the same time, so that apps, shared folders be stored on the SATA SSDs rather than on the 6x 8 TBs HDDs? I assume the 2 SATA SSDs will load apps faster.

Thank you!
QNAPDanielFL
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Re: What m.2 capacity to buy to store Apps, initial shared folder

Post by QNAPDanielFL »

You can later add a new Vdev. But it is usually better for storage efficiency to have just one Vdev for 8 drives.
As for cache, QuTS Hero needs more RAM for cache and the cache experience with 8GB RAM may not be worth the cost of the SSD cache. If you add more RAM then cache can help on random reads but likely won't help on sequential.

So it might be best to just use the M.2 for a system pool for OS + apps and not use cache.

What is the use case? Do you want cache for better sequential performance or just better random read performance?
jang430
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Re: What m.2 capacity to buy to store Apps, initial shared folder

Post by jang430 »

I am just thinking every ZFS file system needs cache for make it go faster. If not needed, I would gladly put this off for a later purchase. Of course, RAM is already in my list of to buys together with the nas. Looking at 16 GB or 32 GB. How do you calculate how much you need? I am looking at better random read performance (cause my files are small, pictures, docs). In that case, which is better to buy first, 2 m.2 for system pool + apps? Or cache? I most probably won't get them both at the same time, as it will cost a lot.

Furthermore, so it is possible to add a new RAID Group (vdev?) to existing RAID Group? So can I start with my 5x 8 TBs and add maybe 3 SATA SSDs in the future? So as long as each RAID Group has some kind of RAID for protection? It also says adding new vdev to an existing vdev, they are joined in RAID 0 fashion.

I've read that it's possible on article below, though quite unsure.

https://docs.qnap.com/operating-system/ ... 5.x/en-us/
QNAPDanielFL
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Re: What m.2 capacity to buy to store Apps, initial shared folder

Post by QNAPDanielFL »

jang430 wrote: Tue Jun 29, 2021 9:43 am In that case, which is better to buy first, 2 m.2 for system pool + apps? Or cache? I most probably won't get them both at the same time, as it will cost a lot.

Furthermore, so it is possible to add a new RAID Group (vdev?) to existing RAID Group? So can I start with my 5x 8 TBs and add maybe 3 SATA SSDs in the future? So as long as each RAID Group has some kind of RAID for protection? It also says adding new vdev to an existing vdev, they are joined in RAID 0 fashion.

I've read that it's possible on article below, though quite unsure.

https://docs.qnap.com/operating-system/ ... 5.x/en-us/
It should be better to add the SSD system pool first if you don't have the money for both the system pool and the cache. Also, you can add cache at any time, but if you later add an SSD pool, it won't be the system pool. The first pool you make is the system pool.
If you later add cache in the future, I expect 32GB RAM will be worth getting.

If you start with 5 drives RAID 5 and later make another Vdev of 3 drives RAID5, then if you make both Vdevs part of the same storage pool, files are striped across both Vdevs much like RAID0.
jang430
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Re: What m.2 capacity to buy to store Apps, initial shared folder

Post by jang430 »

If as discussed, I created a RAID Z1, using 5x 8 TB, then at a later date, added a RAID Z1 3x 1 TB SSD, both RAID Groups will be in RAID 0. If both of them in the same pool, will folders created initially (while there is still no SSD RAID Group) be able to use the additional storage space provided by the newly created SSD RAID Group? After adding SSD RAID Group and adding to the same pool, I plan to activate Qtier so it takes advantage of the SSD RAID Group.

So is it more advantageous to get 32 GB RAM first rather than getting m.2 SSD for caching? Wouldn't getting 32 GB RAM and getting m.2 SSD for caching be redundant? Furthermore, I still can't find what m.2 SSD size cache to get, any calculator for this? I can only find how much RAM to get based on cache size.
QNAPDanielFL
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Re: What m.2 capacity to buy to store Apps, initial shared folder

Post by QNAPDanielFL »

jang430 wrote: Wed Jun 30, 2021 11:28 am If as discussed, I created a RAID Z1, using 5x 8 TB, then at a later date, added a RAID Z1 3x 1 TB SSD, both RAID Groups will be in RAID 0. If both of them in the same pool, will folders created initially (while there is still no SSD RAID Group) be able to use the additional storage space provided by the newly created SSD RAID Group? After adding SSD RAID Group and adding to the same pool, I plan to activate Qtier so it takes advantage of the SSD RAID Group.

So is it more advantageous to get 32 GB RAM first rather than getting m.2 SSD for caching? Wouldn't getting 32 GB RAM and getting m.2 SSD for caching be redundant? Furthermore, I still can't find what m.2 SSD size cache to get, any calculator for this? I can only find how much RAM to get based on cache size.
If the first 5 drive Z1 group is HDDs, the second RAIDZ1 group to add to the storage pool should be HDDs. Folders made on the first RAID group can use the added storage in new RAID groups added to the pool. But SSD RAID groups should not be added to HDD RAID groups in the same pool.

RAM and cache are not redundant. If you have 32GB RAM and regularly read 500GB of data in a day, you might find that 500GB-1TB cache can help because you get much more cache hits with a larger SSD cache than just 32GB RAM. But the cache on QuTS Hero mostly just helps with random reads, not sequential in most cases.

Another reason more RAM and cache are not redundant is the larger cache does not even work without more RAM. With 32GB RAM you can at most use 1TB cache. With 8GB RAM the amount of cache you can use is so small that I don't usually recommend having SSD cache at all.
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Re: What m.2 capacity to buy to store Apps, initial shared folder

Post by jang430 »

If the first 5 drive Z1 group is HDDs, the second RAIDZ1 group to add to the storage pool should be HDDs. Folders made on the first RAID group can use the added storage in new RAID groups added to the pool. But SSD RAID groups should not be added to HDD RAID groups in the same pool.
Sorry, can you clarify that again? If I first created Raid z1 raid group with 3x 1 TB drives, for system and apps, I can also add another Raid Z1 of 5x 8 TB raid group for storage. But if I started with Raid group of 5x 8 TB, I cannot add a Raid group Z1of 1 TB SSDs? It has to be HDDs?

My understanding is by creating 2 different Raid Groups of different types, SSDs and HDDS, on the same pool, allows for Tiering using Qtier. Please enlighten.
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Re: What m.2 capacity to buy to store Apps, initial shared folder

Post by P3R »

jang430 wrote: Tue Jun 29, 2021 9:43 am I am looking at better random read performance (cause my files are small, pictures, docs).
That's not very small files. Also small files doesn't necessarily mean a random load. With a single client that will just be short sequential transfers, one after another.

Only if you have multiple clients concurrently actively working against the NAS will it be a random load. Like if you have 50 or more office workers working against the NAS, then it can become random access at busy hours.
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!
QNAPDanielFL
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Re: What m.2 capacity to buy to store Apps, initial shared folder

Post by QNAPDanielFL »

jang430 wrote: Thu Jul 01, 2021 1:28 am
If the first 5 drive Z1 group is HDDs, the second RAIDZ1 group to add to the storage pool should be HDDs. Folders made on the first RAID group can use the added storage in new RAID groups added to the pool. But SSD RAID groups should not be added to HDD RAID groups in the same pool.
My understanding is by creating 2 different Raid Groups of different types, SSDs and HDDS, on the same pool, allows for Tiering using Qtier. Please enlighten.
QuTS Hero does not support Qtier. So SSDs and HDDs should not be in the same storage pool.
For QuTS hero, the first pool should be SSDs for OS + apps.
Then the HDD pool can be made. Once 1 HDD RAID group has been made for the HDD pool, you can later add more HDD RAID groups to the HDD pool. But SSD RAID groups should not be added to the HDD pool.
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Re: What m.2 capacity to buy to store Apps, initial shared folder

Post by jang430 »

QuTS Hero does not support Qtier. So SSDs and HDDs should not be in the same storage pool.
For QuTS hero, the first pool should be SSDs for OS + apps.
Then the HDD pool can be made. Once 1 HDD RAID group has been made for the HDD pool, you can later add more HDD RAID groups to the HDD pool. But SSD RAID groups should not be added to the HDD pool.
Thank you for this bit of information! For a while, I thought Qtier is available in QuTS Hero. Further clarification, the first SSD Pool created is only limited for OS and apps? It won't be available for storage use? Asking this to know approximately how big SSDs needed for the SSD Pool. You mean to say in a NAS such as TS-873A, 8 bay, assuming you don't use expansion cards, m.2 ideally will go to caching, with the remaining 8 bays, you assign SSD Pool (just for storage and apps), and HDD Pool (for storage)? Since you only have 8 bays, I always thought you can have and SSD RAID Group (vdev) and HDD RAID Group (vdev) in the same pool so that SSD gives you some faster access to commonly accessed files (either via Qtier, or other built-in ZFS feature that I didn't know about :D ) while less frequently accessed files stay in HDD RAID Group.

In this case, if SSD pool cannot be mixed with HDD pool, you automatically start with 2 pools correct?

If SSD pools is only for Apps and system, I think RAID 1 mirroring will be enough, 2 bay. I will be left with 6 bays, with existing 5x 8 TB disks, it would be better to start immediately with 6x 8 TBs in RAID Z1, or 2 RAID Z1 Groups of 3x 8 TBs each?
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Re: What m.2 capacity to buy to store Apps, initial shared folder

Post by jang430 »

P3R wrote: Thu Jul 01, 2021 2:12 am
jang430 wrote: Tue Jun 29, 2021 9:43 am I am looking at better random read performance (cause my files are small, pictures, docs).
That's not very small files. Also small files doesn't necessarily mean a random load. With a single client that will just be short sequential transfers, one after another.

Only if you have multiple clients concurrently actively working against the NAS will it be a random load. Like if you have 50 or more office workers working against the NAS, then it can become random access at busy hours.
This will be a NAS for the house only, so users will be 6 the most. Given this info, which item can I do without to keep cost down? How much SSD cache will eventually be recommended if I have 6x 8 TBs? I know the RAM will depend on the SSD cache size right?

BTW, I think I should mention now that the content of the NAS will be photos, videos, and some documents such as word, excel, and pdfs. Nothing else. I was re-reading your comments from the beginning, this will mean these files will be sequential access? And if sequential access, an SSD cache isn't all that necessary?

If above is correct, then the plan would be:

get TS-873A, memory 16 GB
get 2x m.2 500 GB SSD for System pool + apps
Either work with my existing 5x 8 TBs, or get another 8 TB to have 6x in total (depending on answer of QNAPDanielFL whether SSD RAID group will only be used for apps + system, or whether it can also be used for storage at the same time, as this will determine how many SSDs I'll be getting, 2 or 3)
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Re: What m.2 capacity to buy to store Apps, initial shared folder

Post by P3R »

jang430 wrote: Thu Jul 01, 2021 11:39 am I was re-reading your comments from the beginning, this will mean these files will be sequential access? And if sequential access, an SSD cache isn't all that necessary?
Yes, that's my conclusion.
Either work with my existing 5x 8 TBs, or get another 8 TB to have 6x in total (depending on answer of QNAPDanielFL whether SSD RAID group will only be used for apps + system, or whether it can also be used for storage at the same time, as this will determine how many SSDs I'll be getting, 2 or 3)
Given the intended usage you've told us about, I don't understand what you would do with SSDs as storage? Don't complicate the installation more than necessary and 2*SSDs in mirror is great for the system. But Daniel know this better than me.
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!
QNAPDanielFL
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Re: What m.2 capacity to buy to store Apps, initial shared folder

Post by QNAPDanielFL »

I think it makes the most sense to just use the M.2 slots for the system pool and then you have 8 HDD bays you can use for storage. You are allowed to store data on the system pool as well, but if you mostly want sequential access, 8 HDD should work well for that. So I think a small System pool of just 2 SSDs makes sense. If you increase the RAM, the throughput should be higher. But if you have to keep to a budget, you can try with just the 8GB RAM for now and see if it is fast enough for what you need it to do.
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