BUILD Dell R610 with Perc 6i versus SAS 6/IR? (JBOD)

[victorhooi]

Hi,

We have a Dell R610 server that we just purchased.

It comes with a Dell Perc 6i SATA/SAS controller card inside. We're currently using this with 2.5" SATA disks.

I was trying to configure this, and noticed that it supports RAID-0, RAID-1 and RAID-5 - but not JBOD.

I've heard that apparently there's a Dell SAS 6/IR card that is simpler, but does support JBOD. And apparently, it does support SATA drives.

However, it apparently has not backup battery. I'm just wondering, what else do we lose by going to the SAS 6/IR? Will performance suffer?

Will the lack of a battery mean it doesn't have writeback mode, right?

Or are there other basic SAS/SATA cards you could recommend that suppoort JBOD?

Regards,
Victor

 

[NiKiLLst]

IBM M1015 (flashed to P16 IT mode) is the most common suggestion.

Remember that you shouldn't use hardware raid with freeNas.

Here you can find several advices for FreeNAS hardware: https://forums.freenas.org/index.php?threads/hardware-recommendations-read-this-first.23069/

 

[jgreco]

You're focusing on the wrong thing. With ZFS, ZFS itself is your RAID controller. Putting a RAID controller after a RAID controller is a bad move. Use an HBA for ZFS.

What the PERC calls "JBOD" may or may not be what ZFS needs in order to function properly. What ZFS actually needs is for the hardware to get out of the way, HBA-style.

Most SAS systems support SATA. It's more or less part of the spec.

You do not want your hardware doing writeback tricks outside the control of ZFS. ZFS itself sometimes does benefit from some sort of persistent storage, but depending on your needs this might or might not be an issue.

 

[cyberjock]

Perc doesn't call anything "JBOD". It's literally RAID0, RAID5, and RAID1. That's it. Doing RAID0 is NOT JBOD, and that controller is NOT appropriate for FreeNAS and ZFS.

Frankly, I would not buy a Dell if the intention is to put FreeNAS on it. If you actually plan to use FreeNAS on it you should return it and build your own.

 

[victorhooi]

In this case the Dell R610 server has unfortunately already been purchased, and it's out of my hands...lol.

The IBM M1015 seems to be a popular choice - it is a bit on the pricey side though. Would it be hard to make this work with the R610 chassis/backplane? I don't know what compatibility across these sorts of cards is.

Apart from that, is there anything else we could buy that would simply pass through the disks?

 

[cyberjock]

If there was something cheaper you could use, that would be the recommended card. The M1015 is awesome because it's so inexpensive. $100 for an 8 port SAS controller with 6Gbps support is a SMOKING deal.

 

[jgreco]

Check to see if the backplane has SFF8087 connectors. If it does, then you probably just need the HBA and some SFF8087 cables. Dell also makes the PERC H310 which is basically Dell's version of the M1015 HBA. Like the M1015, it can be crossflashed to IT mode, but the process is less-nice. Does work just fine, though. For deployment in a 2U server, the H310 is a better choice because of the end-facing SFF8087's.

 

[JStarcher]

Correct me if I'm wrong, but can't you flash the Perc 6i with LSI SAS 3081E-R IT firmware to make it a dumb HBA/JBOD? I'm awaiting mine to be delivered but according to this thread it seems like an acceptable solution.

I've considered M1015, sure it's reasonable at $100 but it costs 40% of what I paid for the entire server. I also ordered a Dell SAS 6/IR just incase as it was only $6. I'll report back on my experience with flashing the Perc 6i though.

 

[jgreco]

Threads on HardForum from random people are a great resource. <sarcasmtag>

If you can actually flash it to an HBA with known good driver support, great. I don't recognize the 6i as being capable of that (the Dell PERC H310 and H300 are).

The problem is that even hardware that "works" sometimes fails to work well, and piddling around over a few bucks to attach eight $150 drives is a bit irrational IMHO.

 

[JStarcher]

Threads on HardForum from random people are a great resource. <sarcasmtag>

If you can actually flash it to an HBA with known good driver support, great. I don't recognize the 6i as being capable of that (the Dell PERC H310 and H300 are).

The problem is that even hardware that "works" sometimes fails to work well, and piddling around over a few bucks to attach eight $150 drives is a bit irrational IMHO.

I can definitely agree with that, making hardware do things it's not supposed to do and then expecting it to be stable is ignorant. But any objections to the Dell SAS 6/IR? It officially supports JBOD.

 

[HoneyBadger]

IIRC it doesn't support >2TB drives but if that's not an issue, it should work as a dumb HBA when reflashed with LSI firmware. I'd blow away the boot ROM as well when you're flashing it so that it doesn't try to get any lofty ambitions of handling those drives itself.

The newer H200 reverts to dumb-HBA mode on official firmware if it is left in a fully unconfigured state, but I don't think the SAS6/IR does.

 

[JStarcher]

IIRC it doesn't support >2TB drives but if that's not an issue, it should work as a dumb HBA when reflashed with LSI firmware. I'd blow away the boot ROM as well when you're flashing it so that it doesn't try to get any lofty ambitions of handling those drives itself.

The newer H200 reverts to dumb-HBA mode on official firmware if it is left in a fully unconfigured state, but I don't think the SAS6/IR does.

Right, yes 2TB max is okay for my needs. I'll probably stick with the flashed Perc 6i if it works anyway, since as we know RAID isn't a replacement for backups anyway ;)

 

[cyberjock]

I don't even know what LSI firmware you guys are talking about...

From that thread you linked on hardforums...

fixed the directory structure so that it will work in DOS. Directories on CD:
-12802 = LSI flasher, LSI 1.28.02 firmware
-12900 = LSI flasher, LSI 1.29.00 firmware
-129oldfl = LSI flasher from 1.28.02 package, LSI 1.29.00 firmware
-DellA05 = Dell flasher, Dell A05 firmware (untested by me but this is unmodified from Dell)
-D12802 = Dell flasher, LSI 1.28.02 firmware (untested)
-D12900 = Dell flasher, LSI 1.29.00 firmware (untested)

Those numbers are nothing remotely like the standard LSI firmware that the mps driver uses (p15, P16, etc.). LSI has lots of models of controllers, and not all can be reflashed to an IT mode, and not all work with the mps driver, etc.

It sure looks like you're talking about something that is effectively untested and doesn't give you an equivalent M1015 that is in IT mode.

 

[jgreco]

That's because it's a SAS 3Gbps controller, Cyberjock. We don't see many of those flying around anymore. I've got one or two floating around that I use mostly for OS boot. Units like the ServeRAID BR10i were the M1015 of the 3Gps era and quite popular on FreeNAS at the time, but had all the LSI issues I dismiss in the LSI thread, including the 2TB limit.