@scottalanmiller said in Deciding Between Hardware and Software RAID in My FreeNAS Deployment:

To follow up to an offline request for more info...

Why do you need to avoid splitting RAID duties between a controller, and ZFS?

First, this is a general rule and not specific to any of the tech here. The RAID system just need to be intact, wherever it is.

Now, why is this?

In order for the data integrity systems to be able to do their job and protect the data, there needs to be deep insight and coordination between logical levels and the hardware itself. This is so that components looking for hardware failure can verify higher up the chain if there is a way to reconstruct the data. The layer doing the scrubbing and the parity or mirroring needs to know if the hardware integrity is still there and, if not, what it needs to do to recover. Either layer can do this, hardware or software, but what it can't do is talk between the two.

So if you have all hardware RAID, physical and logical layers can communicate to verify integrity. If you have all software RAID, you can do the same. But if the hardware layer and the logical layer cannot talk to one another, and one of them detects a problem, there is no way to do anything about it. Your overall system has all this information and data protection, but no way to do anything about it - the left hand doesn't know what the right hand is doing.

Hence why it is so important to pick one or the other. Riding the fence and trying to leverage both is where problems arise.

thanks all for reply

so i need:
1- backup my vms and recreate raid on Hardware and just present one logical drive to ZFS.
2-disable S.M.A.R.T service.
3-just use file system and not software RAID system of zfs.

hello to all

in my freenas server, each disk is on Raid0 Hardware Raid P410i and separate raid0 disk present to zfs and use freenas raid and disable S.M.A.R.T services on freenas and let RAID card handles the SMART monitoring, handles the alerting.
I khow i can use hardware raid and present single logical unit to freenas. but our server is under load. should i use hardware raid or continue with exist config ?
what is your idea about this?

@matteo-nunziati said in Deciding Between Hardware and Software RAID in My FreeNAS Deployment:

@saniplastic said in Deciding Between Hardware and Software RAID in My FreeNAS Deployment:

@DustinB3403 said in Deciding Between Hardware and Software RAID in My FreeNAS Deployment:

metadata

metadata?

please explain more.

The config files where the vm is defined. Do not backup the vm disk only. I suppose he referes to this.

I backup with veeam.
whole vm files.

@DustinB3403 said in Deciding Between Hardware and Software RAID in My FreeNAS Deployment:

metadata

metadata?

please explain more.

@Dashrender said in Deciding Between Hardware and Software RAID in My FreeNAS Deployment:

@saniplastic said in Deciding Between Hardware and Software RAID in My FreeNAS Deployment:

@scottalanmiller said in Deciding Between Hardware and Software RAID in My FreeNAS Deployment:

To follow up to an offline request for more info...

Why do you need to avoid splitting RAID duties between a controller, and ZFS?

First, this is a general rule and not specific to any of the tech here. The RAID system just need to be intact, wherever it is.

Now, why is this?

In order for the data integrity systems to be able to do their job and protect the data, there needs to be deep insight and coordination between logical levels and the hardware itself. This is so that components looking for hardware failure can verify higher up the chain if there is a way to reconstruct the data. The layer doing the scrubbing and the parity or mirroring needs to know if the hardware integrity is still there and, if not, what it needs to do to recover. Either layer can do this, hardware or software, but what it can't do is talk between the two.

So if you have all hardware RAID, physical and logical layers can communicate to verify integrity. If you have all software RAID, you can do the same. But if the hardware layer and the logical layer cannot talk to one another, and one of them detects a problem, there is no way to do anything about it. Your overall system has all this information and data protection, but no way to do anything about it - the left hand doesn't know what the right hand is doing.

Hence why it is so important to pick one or the other. Riding the fence and trying to leverage both is where problems arise.

thanks all for reply

so i need:
1- backup my vms and recreate raid on Hardware and just present one logical drive to ZFS.
2-disable S.M.A.R.T service.
3-just use file system and not software RAID system of zfs.

Where are you disabling SMART?

in freenas gui.

@Obsolesce said in Deciding Between Hardware and Software RAID in My FreeNAS Deployment:

@saniplastic said in Deciding Between Hardware and Software RAID in My FreeNAS Deployment:

1- backup my vms and recreate raid on Hardware and just present one logical drive to ZFS.

Just an FYI: it's not a backup when it's the only data. If you back up your VMs, then delete the originals, you no longer have a backup. All you have then is original data with no backup! Proceed wisely.

you right

i should have 2 series of backup.
thanks

@scottalanmiller said in Deciding Between Hardware and Software RAID in My FreeNAS Deployment:

To follow up to an offline request for more info...

Why do you need to avoid splitting RAID duties between a controller, and ZFS?

First, this is a general rule and not specific to any of the tech here. The RAID system just need to be intact, wherever it is.

Now, why is this?

In order for the data integrity systems to be able to do their job and protect the data, there needs to be deep insight and coordination between logical levels and the hardware itself. This is so that components looking for hardware failure can verify higher up the chain if there is a way to reconstruct the data. The layer doing the scrubbing and the parity or mirroring needs to know if the hardware integrity is still there and, if not, what it needs to do to recover. Either layer can do this, hardware or software, but what it can't do is talk between the two.

So if you have all hardware RAID, physical and logical layers can communicate to verify integrity. If you have all software RAID, you can do the same. But if the hardware layer and the logical layer cannot talk to one another, and one of them detects a problem, there is no way to do anything about it. Your overall system has all this information and data protection, but no way to do anything about it - the left hand doesn't know what the right hand is doing.

Hence why it is so important to pick one or the other. Riding the fence and trying to leverage both is where problems arise.

thanks all for reply

so i need:
1- backup my vms and recreate raid on Hardware and just present one logical drive to ZFS.
2-disable S.M.A.R.T service.
3-just use file system and not software RAID system of zfs.

@Dashrender said in Deciding Between Hardware and Software RAID in My FreeNAS Deployment:

This thread covers exactly what you are asking about.
https://mangolassi.it/topic/12047/zfs-is-perfectly-safe-on-hardware-raid/

i read that several time and find out zfs can implement on top of the raid controller.but can not get my answer related to my question.

@scottalanmiller said in Deciding Between Hardware and Software RAID in My FreeNAS Deployment:

Cache-less RAID of any sort is all but useless

thanks for reply

before The more I read, the more I get confused :

FreeNAS 11.2- User Guide, Release 11.2 in page 322 says that:

"ZFS was designed for commodity disks so no RAID controller is needed. While ZFS can also be
used with a RAID controller, it is recommended that the controller be put into JBOD mode so that ZFS has full control of the disks"

it says it is not needed ( not explicitly don't use ) and While ZFS can also be used with a RAID controller.

and in page 110 says that:

To prevent problems, do not enable the S.M.A.R.T. service if the disks are controlled by a RAID controller. It is the job of the controller to monitor S.M.A.R.T. and mark drives as Predictive Failure when they trip.

it means this is possible to use RAID controller by freenas

But in freenas forum every time you ask for Hardware RAID and zfs , all strictly says NO, DO NOT DO THAT.
When I read your article, I was happy to find out.

I use P410i (1G chache) on DL380 G7 and as i said raid0 each drive and present separate raid0 to freenas.
i have one mirror pool and one Raidz1 pool and one Raidz2 pool.

If I understand well because raid controller have 1G cache i should use Hardware RAID and present one logical drive to freenas and not using zfs raid.

am i right?

@scottalanmiller said in Deciding Between Hardware and Software RAID in My FreeNAS Deployment:

@saniplastic said in Deciding Between Hardware and Software RAID in My FreeNAS Deployment:

in my freenas server, each disk is on Raid0 Hardware Raid P410i

How much cache does this have?

1G

hello to all

in my freenas server, each disk is on Raid0 Hardware Raid P410i and separate raid0 disk present to zfs and use freenas raid and disable S.M.A.R.T services on freenas and let RAID card handles the SMART monitoring, handles the alerting.
I khow i can use hardware raid and present single logical unit to freenas. but our server is under load. should i use hardware raid or continue with exist config ?
what is your idea about this?