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Date:      Fri, 23 Jan 2015 20:21:05 +1000
From:      David Gwynne <david@gwynne.id.au>
To:        Ahmed Kamal <email.ahmedkamal@googlemail.com>
Cc:        freebsd-scsi@freebsd.org
Subject:   Re: Dell branded storage controller for ZFS file-server | Advice requested
Message-ID:  <EDB1FFA8-5311-4846-BCFF-127DF9A71453@gwynne.id.au>
In-Reply-To: <CANzjMX4GXf_jMMKZVSE3kf4NCvOUR0anjda3KSvFTNn6-%2BWmGg@mail.gmail.com>
References:  <CANzjMX4GXf_jMMKZVSE3kf4NCvOUR0anjda3KSvFTNn6-%2BWmGg@mail.gmail.com>

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> On 23 Jan 2015, at 7:16 pm, Ahmed Kamal =
<email.ahmedkamal@googlemail.com> wrote:
>=20
> Hi everyone,
>=20
> I'm looking to build a ZFS file-server, unfortunately I'm locked into =
Dell
> branded hardware only. I know Dell sometimes ships LSI branded cards, =
but
> that too probably won't work for me, as I live outside the US and the =
local
> Dell rep is clueless (so whatever I want to buy, has to be on Dell's
> website). I am considering Dell R720xd or R730xd. I will use Intel =
i350
> NICs, and ECC RAM, but the biggest questions are around the SAS HBA
>=20
> Per my research, I have the following notes and questions. =
Appreciating
> your comments on them
>=20
> * H310 Card supports syspd (jbod) mode per
> http://svnweb.freebsd.org/base?view=3Drevision&revision=3D254906 so it =
is
> probably the best card for what I want to do, right?

no.

> * H310 is a low end card, it has very limited queue depth (25 I =
believe) ..
> Is this actually a problem when using the disks (20 x SAS 10k disks) =
in
> syspd/jbod mode? what about if I attach a couple of SSD disks?

there are two queue limits here, one for the controller and one for each =
disk attached to it.

h310s have a controller queue depth of 31, ie, they can only support 31 =
commands at a time. if you have 24 disks and distribute the controllers =
command slots between them, thats about 1 command per disk.

> * H310 can be flashed to IT mode (LSI firmware), and is supported by
> Illumos kernel (if I'll ever need that) .. so overall it looks like a =
good
> option. Any "watch-outs" I should be aware of ?

yes. if you flash the h310 to become an sas hba, the pci product/vendor =
and subproduct/subvendor ids on the controller change. the dell bios =
will refuse to boot if it detects an unsupported controller in its =
storage slot. you'll brick the machine until you remove the h310. =
because it is on a non standard mezzanine connector you will not be able =
to flash it back to a h310, and you'll have a useless chunk of silicon =
to put on your desk as a monument to how annoying vendors are.

> * H710/p have no way of exposing JBOD/syspd in any way .. If using =
those
> cards, the best I can do, is to create a raid-0 per disk, and put zfs =
on
> top of that. How bad is this? Is the only problem that I'm locked into =
H710
> firmware? Would the nvram and bbu on H710 improve performance =
significantly
> vs H310?

i wouldnt run zfs on that.

> * H330 and H730, seem supported by mrsas driver. Is this driver able =
to
> expose jbod/syspd mode? If yes, what's the overall advise, should I go =
with
> one of those, or the "trusty" H310 ?

thats a workable option. h330 should be fine if all you want to do is =
jbod.

>=20
> Your help and advice is most appreciated
> _______________________________________________
> freebsd-scsi@freebsd.org mailing list
> http://lists.freebsd.org/mailman/listinfo/freebsd-scsi
> To unsubscribe, send any mail to =
"freebsd-scsi-unsubscribe@freebsd.org"




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