Raid Z with multiple controllers + SATA speeds?

[benni2]

hi folks,

i'm planning on setting up a raidz2 with 6+2 drives. they will be spread over 3 different controllers of which 2 support sata 6gbit mode and one of them supports only 3gbit.

could that lead to a problem in any form? or do i have to hope that there's an option in the firmware / a jumper to limit the sata mode to 3 gbit?

thank you very much in advance.

cheers,
benni

 

[SweetAndLow]

assuming you are using hard drives and not ssd's this is not a problem.

Why have 2 disks on a controller? This isn't usually something people do. You could do something like this if you wanted to eliminate a controller failure from taking down your pool but most people don't get this serious until they have 24+ drives.

 

[benni2]

thank you for your fast reply :)

my description was a bit misleading. i'm planning a raidz2 with a total of 8 drives (where only 6 are usable and 2 are for parity-information). and they will be plugged into the 3 controllers totally randomly. the idea was not to have a 24/7 available space but to have an archive that's not loosing any data :) so if a controller fails, i can wait 3 days until a new one has been shipped.

ok, anyway... your answer helped me. thanks again :)

cheers,
benni

 

[Ericloewe]

You should probably tell us more about your plans. It sounds like you want to implement a solution in search of a problem.

 

[gpsguy]

Ditto what the other responders have said. I can't envision how spreading 8 drives over 3 controllers will give you redundancy against controller failure.

I could see it, if you were doing say two way mirrors and put the two drives on different controllers. But 8 drives in RAIDz2 across 3 controllers doesn't make sense to me.

 

[Mirfster]

Personally, I would opt for simply connecting all the drives to a single controller and shipping the unit with a "cold spare" controller that could be shelved with the unit. However, if there is that much concern over a potential HBA failure, then could the same not be said for any other "single points of failure" (ex. Motherboard)?

 

[Stux]

As I understand it, the correct way to deal with controller failure is to use dual ported SAS drives. Each port connected to a different controller.

Not sure how that works.

 

[benni2]

ok, thanks again for all your answers.
my point is really NOT about controller redundancy. i'm just blessed with a mainboard that uses two different controllers to address 6 drives and a cheap pcie-controller where the other 2 devices will be plugged in.

 

[SweetAndLow]

You should probably tell us what those controllers are and what hardware you have.

 

[benni2]

ok...
mainboard will be a "gigabyte GA-PA65-UD3-B3" which has two controllers onboard:
1) intel H61 chipset - 4x sata 3gbit
2) marvell 88SE9172 - 2x sata 6gbit

and an external pcie-controller is planned:
InLine 76617E with marvell 88SE9215 chipset (4x sata 6gbit)

i will use following drives (4 tb each):
6x HGST HMS5C4040BLE640
1x Seagate ST4000DM000
1x WD WD40EZRX

the last two, i've already got in stock, that's why i'm using different models in my raid. but for my understanding, that shouldn't matter as long as the sizes are identical.

 

[SweetAndLow]

Are you sure those marvell controllers work? Marvells are usually very cheap and the drivers on freebsd are not that good. The suggested controller is a lsi 9211 or ibm m1015

 

[Mirfster]

ibm m1050

FTFY: IBM M1015

 

[benni2]

i don't know if they work :) i haven't researched that, yet. i saw that the lsi 9211 starts at 150 euros, so that's not an option :)
if the drivers are not that good, but stable, i'm fine. i probably won't get the full gbit through the lan, anyway, with my older hardware. if i get 40 mbyte/sec through the lan, i'm happy.

is there a controller compatibility list somewhere?

 

[SweetAndLow]

The controllers will cause drives to drop out of pool because of timeouts and your system will be unstable. eBay has 9211's for ~$100usd

 

[benni2]

thanks for the warning.. :/
unfortunately, ebay is not the solution, either. at least not in germany. the controllers cost 150+ euros there as well or they come from hongkong where nobody knows, what you get ;)

anyway: at least the external marvell 88SE9215, i'm going to buy, seems to work. a guy from this board tested it here --> https://forums.freenas.org/index.php?threads/small-sata-controller-compatibility.40103/#post-252366
maybe i'll plug in 4 drives there and 4 drives onto the intel onboard sata controller and leave the second (onboard) marvell controller empty.

 

[snaptec]

Are you from Germany?
I can send you a working used m1015 ibm Card for 140€. Drop me a pm If you are interested.


Gesendet von iPhone mit Tapatalk

 

[benni2]

thanks for the offer ;) but i'm really hoping that i can bring this server to life much cheaper. in fact: i already ordered the cheap marvell card (40 euros vs. 140 :) ).

it could take a while until all drives have been checked and my data has been copied to the raidz. but afterwards, i'll probably have insights if the controller is working fine or not. and i'm going to post my experiences here.

 

[benni2]

ok, the freenas system is running for a few weeks now and has been loaded with lots of data. so far, i had no problems with the controller. i'm not using it under heavy load, but just as a more or less static storage system.

for my requirements, this controller is perfectly fine (and cheap :) ) --> InLine 76617E with marvell 88SE9215 chipset (4x sata 6gbit)