So what if i use hardware RAID?

[ddaenen1]

I have read the threads around it but not found answers to my questions.

I have a unique opportunity to hook up my supermicro server, which only has 2 2.5" drive bays and thus expansion possibilities, with a Dell MD1000 and a Dell PERC 6/E RAID controller which would give me everything i want:

1. i can use the drive bays of the supermicro server to house 2 SSD's in RAID1 with FreeNAS installed on it instead of the USB thumdrive i use now.
2. I have the possibility to have flexible expansion as i need more space. 15 Bays will maximum allow me 30Tb which i going to pretty future proof for my needs.
3. The MD1000 enclosure allows mixed drive sizes and mixed SAS/SATA drives which means i can use most of my current HDD stock
4. I can use RAID 5 instead of the current RAID 1 and with that maximize the usage of the drives capacity.

The caveat to all of this is that the PERC 6/E controller does not support JBOD and thus, i will need to configure the drives using the hardware RAID. There are many threads mentioning that ideally, ZFS would manage the RAID but in this setup, i don't have any other opportunity. Buying a separate PERC 5/E SAS controller that supports JBOD is possible but why would i spend that much money when i have a PERC 6/E?

So, the plan is to configure the MD1000 in split mode, with 1 x 7 drives and 1 x 8 drives both configured in RAID 5. So, here my questions:

1. How will FreeNAS recognize this setup? I would assume as 2 drives, correct?
2. IF FreeNAS recognizes 2 drives, will ZFS allow me to configure them in RAID 0?
3. If i add a drive or change a drive to a bigger size, will FreeNAS recognize this and autoexpand the pool size?

Any other insights are also welcomed.

Many thanks, Dominique

 

[Jailer]

This is a plan destined for failure. Apparently you missed all the threads where people have lost all their data because they did what you are planning on doing.

 

[ddaenen1]

This is a plan destined for failure. Apparently you missed all the threads where people have lost all their data because they did what you are planning on doing.

OK, so is all of it destined for failure or just part of it and if so, which part?

 

[Ericloewe]

1. How will FreeNAS recognize this setup? I would assume as 2 drives, correct?

Yes.

2. IF FreeNAS recognizes 2 drives, will ZFS allow me to configure them in RAID 0?

Allow? Yes. Is it going to be reliable? No.

3. If i add a drive or change a drive to a bigger size, will FreeNAS recognize this and autoexpand the pool size?

No. That will not work seamlessly and may not work at all without enough effort to make the whole venture pointless. That's the beauty of hardware RAID (/s) everyone does things differently with little regard for anything beyond the bare minimum being compatible.

Other things that will break:

• Expect performance to become patgologically bad in the mid-term future
• Expect data integrity to be a problem. ZFS will be able to detect any problems, but not fix them.
• Monitoring. Expect to rely on crappy vendor applications to monitor your disks.
• Driver support may be poor. That'll depend on the specifics, though.

 

[ddaenen1]

Yes.


Allow? Yes. Is it going to be reliable? No.


No. That will not work seamlessly and may not work at all without enough effort to make the whole venture pointless. That's the beauty of hardware RAID (/s) everyone does things differently with little regard for anything beyond the bare minimum being compatible.

Other things that will break:

• Expect performance to become patgologically bad in the mid-term future
• Expect data integrity to be a problem. ZFS will be able to detect any problems, but not fix them.
• Monitoring. Expect to rely on crappy vendor applications to monitor your disks.
• Driver support may be poor. That'll depend on the specifics, though.

Many thanks for the feedback and insights. Would setting up the MD1000 as in unified mode so FreeNAS only sees one volume and let the hardware just manage RAID5 be a better approach? Would this way FreeNAS recognize size increases and autoexpand?

Considering the potential issues ith the RAID controller, i guess a SAS 5/E controller that can be configured in JBOD would be the best solution as this is a HBA controller, right?

 

[Herr_Merlin]

Go for an HBA.
There is no point in using ZFS or FreeNas if you are going for a hardware RAID. If you go for a hardware RAID go for another OS. Hell even with Windows server and ReFS, Storage Space etc. you want an HBA nowadays and no RAID.

 

[ddaenen1]

Go for an HBA.
There is no point in using ZFS or FreeNas if you are going for a hardware RAID. If you go for a hardware RAID go for another OS. Hell even with Windows server and ReFS, Storage Space etc. you want an HBA nowadays and no RAID.

I get that from all the documentation on FreeNAS that i read but i just wanted to check it out because the MD1000 i bought has a RAID controller included so i just wanted to check what my options are before i go out and buy a HBA controller.

 

[Herr_Merlin]

The point is that ZFS is designed to handle the disk itselfs and thus going for a hardware RAID is not intended or covered in any way by the file system nor was it planned or implemented in it.
Sure you can theoretically misuse any tool for the not designed workload but than you have to suffer the consequences. For some tools they might be low but in this case they are horrible.

 

[ddaenen1]

Many thanks for the feedback and insights. Would setting up the MD1000 as in unified mode so FreeNAS only sees one volume and let the hardware just manage RAID5 be a better approach? Would this way FreeNAS recognize size increases and autoexpand?

Still wondering if FreeNAS would recognize a volume increase when the hardware RAID5 is expanded.

 

[garm]

Search and you will find; a recent thread from a user unable to expand the pool as ZFS do not expect a physical drive to magically and suddenly grow an extra plate.
Don’t use hardware raid..

 

[Chris Moore]

ZFS was intended from inception to have direct access to the physical drives. If you use a hardware RAID controller instead, you are putting your data at extreme risk. I have seen more than six situations over the last few years, here on the forum, where people lost all their data because of a RAID controller scrambling the info that ZFS needed to be able to function.

Just don’t do it.

 

[Chris Moore]

FreeNAS® Quick Hardware Guide
https://www.ixsystems.com/community/resources/freenas®-quick-hardware-guide.7/

Hardware Recommendations Guide Rev. 1e) 2017-05-06
https://www.ixsystems.com/community/resources/hardware-recommendations-guide.12/

Hardware Recommendations by @cyberjock - from 26 Aug 2014 - and still valid
https://www.ixsystems.com/community/threads/hardware-recommendations-read-this-first.23069/

Don't be afraid to be SAS-sy
https://www.ixsystems.com/community/resources/don't-be-afraid-to-be-sas-sy.48/

Confused about that LSI card? Join the crowd ...
https://www.ixsystems.com/community/threads/confused-about-that-lsi-card-join-the-crowd.11901/

 

[ddaenen1]

Well, this situation resolved itself. When i went to pick up the MD1000 today, it appeared that the seller had a PERC 6/E to go with it but also a PERC H200 flashed in IT mode with cable and all so when i mentioned FreeNAS, he offered me the H200 instead of the PERC 6/E. Came home, installed the H200 in my supermicro server, plugged in all cables and everything worked from the first time. HBA booted, recognized the 4 drives i had installed in the MD1000 and the rest is history. FreeNAS installation from scratch went flawless too and i am now at the stage that i am configuring all options i need in FreeNAS up to the point where i need to go configure the pool. I want to wait with that until i have drives for all 15 slots as it was made very clear that you cannot add drives to a pool or a vdev but you can add vdevs to a pool :)

So i am still contemplating if i want all drives in one vdev or not or if i only want one pool or 2 pools. This Freenas server will be used for Plex in the first stage. Any thoughts?

 

[Mannekino]

It depends on the raid level of a vdev and how many drives you want. If you use RAIDZ1 I personally would keep it between 4-6 drives. With RAIDZ2 you can go higher of course. Somewhere between 8-12 per vdev. Also depends on what data you will be storing, how important it is and what risk level you're comfortable with. For my home media storage (movies and such) I use a RAIDZ1 pool with 4 drives. And I'm planning to expand the pool soon with another 4 drives in a vdev. If I would want to store lots of data I would use either RAIDZ2 or a full mirrored setup.

 

[Ericloewe]

15-wide is too wide, unfortunately. Maybe 7+7+a hot spare?
Edit, to clarify: it works, but it'll get very sucky, soonish.

 

[ddaenen1]

15-wide is too wide, unfortunately. Maybe 7+7+a hot spare?
Edit, to clarify: it works, but it'll get very sucky, soonish.

Thanks for the advice. I am thinking 2 pools with 8 and 7 as i am planning to use the MD1000 in unified mode but it can also work in a 7/8 split mode serving 2 different servers from the 2 separate EMM's. Might come in handy in the future if i want to use this functionality without having to kill the pool for the Plex server and set it up again.