How do I go about connecting hard drives to my server?

[cadabri]

Hey guys! I just recently picked up an R720 server from craigslist for 350 bucks to use as a NAS with Freenas. Everything seems to be great with it, dual e5-2640s, 32 gigs of ram, the works, however the one thing I am confused about is connecting the drives. As is, the server has 8 hot swap drives in the front which connect to an SAS backplane, then go directly into the motherboard, but the part that gets tricky, is there is also a raid controller that goes direcly into the motherboard as well. A friend of mine has said that it is absolutely imparitive to not use a raid controller as Freenas uses ZFS. My question is though, since the hard drives are not setup HDD>RAID>MB but HDD>MB RAID>MB should I not be able to just disable the raid controller in the BIOS and be fine?

 

[milantheworse]

just plug a sata in l.o.l

[Mr Technician]

11 minutes ago, cadabri said:

Hey guys! I just recently picked up an R720 server from craigslist for 350 bucks to use as a NAS with Freenas. Everything seems to be great with it, dual e5-2640s, 32 gigs of ram, the works, however the one thing I am confused about is connecting the drives. As is, the server has 8 hot swap drives in the front which connect to an SAS backplane, then go directly into the motherboard, but the part that gets tricky, is there is also a raid controller that goes direcly into the motherboard as well. A friend of mine has said that it is absolutely imparitive to not use a raid controller as Freenas uses ZFS. My question is though, since the hard drives are not setup HDD>RAID>MB but HDD>MB RAID>MB should I not be able to just disable the raid controller in the BIOS and be fine?

 

Just make sure the controller is in IT mode. I've got an LSI H220 in my freenas and it works flawlessly, which I bought off Ebay already flashed.

[cadabri]

Just now, milantheworse said:

just plug a sata in l.o.l

What do you mean? The hard drive goes into a backplane and from there goes out with a different cable that is not sata. 

[cadabri]

Just now, ThatFlashCat said:

Just make sure the controller is in IT mode. I've got an LSI H220 in my freenas and it works flawlessly, which I bought off Ebay already flashed.

I'm not really sure how to do that with the controller, its not plugged into a pci-e port but just lays on the MOBO, however in the BIOS there is an option to turn it off. 

[milantheworse]

i am kinda drunk.. sorry uuhm tomarrow i give a awnser XD greatings from russia

[cadabri]

3 minutes ago, ThatFlashCat said:

Just make sure the controller is in IT mode. I've got an LSI H220 in my freenas and it works flawlessly, which I bought off Ebay already flashed.

https://imgur.com/a/3h7SjMj

In this photo you can see where the hard drive backplane plugs into the MOBO, and the raid controller right next to it

[Windows7ge]

You will want an HBA (Host Bus Adapter) or a RAID card that has had it's firmware flashed to IT mode.

 

The reason is RAID cards interfere with the way the drives communicate with the OS. ZFS likes direct access to the drives to manage them and maintain data integrity. RAID controllers cause this communication to be broken. The system can still work with a RAID controller in place while using ZFS but you'll have lost the biggest features that make ZFS what it's known for.

 

ZFS doesn't care about using different controllers or chipsets. If the BIOS allows you to change the onboard controller from RAID to AHCI then that should be fine. These drives can be mixed with drives on other controllers like an HBA or an IT flashed RAID card.

[cadabri]

9 minutes ago, Windows7ge said:

You will want an HBA (Host Bus Adapter) or a RAID card that has had it's firmware flashed to IT mode.

 

The reason is RAID cards interfere with the way the drives communicate with the OS. ZFS likes direct access to the drives to manage them and maintain data integrity. RAID controllers cause this communication to be broken. The system can still work with a RAID controller in place while using ZFS but you'll have lost the biggest features that make ZFS what it's known for.

 

ZFS doesn't care about using different controllers or chipsets. If the BIOS allows you to change the onboard controller from RAID to AHCI then that should be fine. These drives can be mixed with drives on other controllers like an HBA or an IT flashed RAID card.

Well like I was saying, the hard drives are plugged directly into the motherboard, however looking into the bios, it looks like I should be able to change it to AHCI. Is this effectively like having the HBA?

 

https://imgur.com/a/Ecq5wpX - Here are the settings I have access to

[Windows7ge]

1 minute ago, cadabri said:

Well like I was saying, the hard drives are plugged directly into the motherboard, however looking into the bios, it looks like I should be able to change it to AHCI. Is this effectively like having the HBA?

 

https://imgur.com/a/Ecq5wpX - Here are the settings I have access to

That would likely be apart of the onboard chipset. Setting this to AHCI should suffice.

 

You can disable the RAID controller if you like. You probably won't be able to plug anything into it though if you do.

[cadabri]

2 minutes ago, Windows7ge said:

That would likely be apart of the onboard chipset. Setting this to AHCI should suffice.

 

You can disable the RAID controller if you like. You probably won't be able to plug anything into it though if you do.

If you look at the image I sent to ThatFlashCat - https://imgur.com/a/3h7SjMj - there is nothing to plug into the raid controller. The raid controller goes directly into the MB, and that cable to the right of that board is where all the SAS drives are being plugged into the MB

[Windows7ge]

6 minutes ago, cadabri said:

If you look at the image I sent to ThatFlashCat - https://imgur.com/a/3h7SjMj - there is nothing to plug into the raid controller. The raid controller goes directly into the MB, and that cable to the right of that board is where all the SAS drives are being plugged into the MB

I'm not a Dell server guru but it's popular for Dell to do things like this where a controller will slot in or connect to a socket and the ports for it are on the board itself. Without the card the ports just wont work.

 

You can look up the manual for your server which may provide you information on that or you can disconnect the RAID card and see if devices still show up on those ports. If not then they're for the RAID card.

[Jarsky]

Thats a PERC H310/H710 controller card. The ports on the motherboard communicate with that controller.

Older Dell Servers had a dedicated PCI-E slot for the integrated controller which would be a PCI-E card but would have firmware that dedicated it for the integrated raid slot. A standard RAID card doesn't work in the integrated RAID slot.  

They changed it in the Rx20 series from a PCI-E card to a plug in daughter board. Probably because of it taking an unnecessary amount of room, and for the problem above where people would try and swap the RAID card and wonder why it wouldn't work (Third Party aka. non integrated RAID cards, go in one of the standard PCI-E expansion slots). 

[Nick7]

Since ZFS 'likes' to use direct drives, one workaround is to simple create 8 logical drives - one logical drive per physical hard drive. This way ZFS can still detect errors on disk due to checksum, etc.

It is one extra layer that you do not need with ZFS, but in the end, it doesn't hurt much either.

[AbydosOne]

On 10/22/2019 at 7:41 AM, Nick7 said:

This way ZFS can still detect errors on disk due to checksum, etc.

AFAIK, this won't work, because a RAID of one drive won't present the drive SMART data.

[Nick7]

On 10/25/2019 at 6:56 PM, AbydosOne said:

AFAIK, this won't work, because a RAID of one drive won't present the drive SMART data.

SMART has nothing to do with checksum ZFS does.

ZFS itself does not in any way check/use SMART data.

 

Yes, with having each drive as logical volume, you lose access to SMART data from OS directly, but if you need it, you can still access it with raid controller tools.

Other than that, there is no real difference between logical volume vs physical disk.

[Olaf6541]

On 10/25/2019 at 6:56 PM, AbydosOne said:

AFAIK, this won't work, because a RAID of one drive won't present the drive SMART data.

42 minutes ago, Nick7 said:

Yes, with having each drive as logical volume, you lose access to SMART data from OS directly

You can always access the SMART data of each individual physical drive, it is not really relevant what volumes or raid configurations you have on those drives...

Only if you let a RAID chip ("hardware RAID") handle the communication with the drives then your OS cannot get SMART data but that is exactly what you do not want with ZFS.

[Salacious B Crum]

On 10/21/2019 at 2:23 AM, Jarsky said:

where people would try and swap the RAID card and wonder why it wouldn't work (Third Party aka. non integrated RAID cards, go in one of the standard PCI-E expansion slots). 

Can confirm my R710 did not like my HBA installed in the proprietary slot the the raid controller was in, put it in another X8 slot and works like a charm

[Nick7]

23 hours ago, Olaf6541 said:

Only if you let a RAID chip ("hardware RAID") handle the communication with the drives then your OS cannot get SMART data but that is exactly what you do not want with ZFS.

It does not matter to ZFS, nor impacts error handling by ZFS.

ZFS does not read or use SMART data.

FreeNAS or similar know to read SMART and give alerts, etc... but - ZFS itself has nothing to do with SMART.

It's similar as myth of 1GB of RAM for 1TB of space under ZFS. Even without dedup. Or ECC memory required.

[Olaf6541]

4 hours ago, Nick7 said:

It does not matter to ZFS, nor impacts error handling by ZFS.

ZFS does not read or use SMART data.

Correct, I meant if your aim is to use ZFS and you use it the right way your OS would always be able to see SMART data because youre not using hardware raid.

The SMART data itself is accessed by the OS and has indeed nothing to do with ZFS or anything else on the disks.

[Thirdgen89GTA]

On the physical side of things.  SAS ports are backwards compatible with SATA drives.  Aka, you can plug a SATA drive into a SAS port and it will work just fine. (Just not a SAS drive into a SATA port)

 

On the logical side of things, FreeNAS ZFS wants direct logical access to the disk.  A Raid card in IR mode will interfere with this and can cause data corruption.  So what you want is is a Raid card capable of being firmware flashed to IT mode.  IT mode disables the RAID feature set, and makes the RAID card act like a Host Bus Adapter.

 

The flash process is slightly different for every card, but many cards use the same chipsets so you can cross flash with a different firmware.

 

[Nick7]

15 hours ago, Thirdgen89GTA said:

On the logical side of things, FreeNAS ZFS wants direct logical access to the disk.  A Raid card in IR mode will interfere with this and can cause data corruption.  So what you want is is a Raid card capable of being firmware flashed to IT mode.  IT mode disables the RAID feature set, and makes the RAID card act like a Host Bus Adapter.

Please do not spread FUD.

 

IR vs IT mode is same for data consistency and error handling. There is no 'interfering' and/or causing data corruption.

 

Main difference is in IT mode you skip all 'logic' that RAID card has, which in the end can benefit from better performance, easier obtaining SMART status and easier handling in case of disk failure (no need to go into RAID card config&it's tools).

 

Saying that IR mode can cause data corruption is completely false and simple FUD.

 

Only way to cause data corruption is to use write back on RAID card without BBU, but that is different story (read: stupidity).