[OpenIndiana-discuss] sata hba choice

[Timothy Coalson]

Would, say, a scrub cause that kind of bus contention, and trigger the
bad behavior?  That would be rather problematic for ZFS if you
couldn't even scrub your pool without devices dropping.  I ask because
I built a storage system with SATA on LSI HBAs, luckily went with
direct connection without knowing about the SATA on SAS expander
issue, but was planning on using cascading expanders if more storage
was needed.

Tim

On Fri, Aug 24, 2012 at 3:48 PM, Sašo Kiselkov <skiselkov.ml at gmail.com> wrote:
>
> There's a huge difference between home rigs and enterprise builds. Sure
> I'm running lower-spec hardware for home use. No need to use SAS for
> that, I'm very happy with my HP MicroServer, it has 8GB of ECC DRAM, 6
> on-board AHCI SATA ports and I've loaded it up with WD Red drives (rated
> for 24x7 around the clock operation), a 60GB Vertex 3 l2arc, all well
> under $1000.
>
> SATA on SAS buses will work for most scenarios and if you're not putting
> high strains on your hardware, you should be okay. What I'm arguing
> against (and many other people are) is putting them in high-performance
> rigs where the bus is going to see lots of contention, high data volumes
> with very little tolerance to error or outages.
>
> Cheers,
> --
> Saso
>
> On 08/24/2012 10:31 PM, Robbie Crash wrote:
> > So what's the best option for people like myself, running a home server,
> > that don't have the extra $300 to drop on every hard drive? I'm coming up
> > on 90% full on my pool, so I'm going to need to expand or replace. I'd
> > rather buy some disks and an expander like this one:
> > http://<http://www.amazon.com/Intel-RAID-Expander-Card-RES2SV240/dp/B0042NLUVE/ref=sr_1_1?ie=UTF8&qid=1345839377>
> > www.amazon.com<http://www.amazon.com/Intel-RAID-Expander-Card-RES2SV240/dp/B0042NLUVE/ref=sr_1_1?ie=UTF8&qid=1345839377>
> > /Intel-RAID-Expander-Card-RES2SV240/<http://www.amazon.com/Intel-RAID-Expander-Card-RES2SV240/dp/B0042NLUVE/ref=sr_1_1?ie=UTF8&qid=1345839377>
> > dp<http://www.amazon.com/Intel-RAID-Expander-Card-RES2SV240/dp/B0042NLUVE/ref=sr_1_1?ie=UTF8&qid=1345839377>
> > /B0042NLUVE/ref=sr_1_1?<http://www.amazon.com/Intel-RAID-Expander-Card-RES2SV240/dp/B0042NLUVE/ref=sr_1_1?ie=UTF8&qid=1345839377>
> > ie<http://www.amazon.com/Intel-RAID-Expander-Card-RES2SV240/dp/B0042NLUVE/ref=sr_1_1?ie=UTF8&qid=1345839377>
> > =<http://www.amazon.com/Intel-RAID-Expander-Card-RES2SV240/dp/B0042NLUVE/ref=sr_1_1?ie=UTF8&qid=1345839377>
> > UTF8<http://www.amazon.com/Intel-RAID-Expander-Card-RES2SV240/dp/B0042NLUVE/ref=sr_1_1?ie=UTF8&qid=1345839377>
> > &<http://www.amazon.com/Intel-RAID-Expander-Card-RES2SV240/dp/B0042NLUVE/ref=sr_1_1?ie=UTF8&qid=1345839377>
> > qid<http://www.amazon.com/Intel-RAID-Expander-Card-RES2SV240/dp/B0042NLUVE/ref=sr_1_1?ie=UTF8&qid=1345839377>
> > =1345839377<http://www.amazon.com/Intel-RAID-Expander-Card-RES2SV240/dp/B0042NLUVE/ref=sr_1_1?ie=UTF8&qid=1345839377>
> > than have
> > to buy a whole new motherboard so I can add another full controller. I
> > don't have any open PCIe slots, and SATA over PCI is a waste of everything.
> >
> > Are the issues with SATA over SAS expanders that prevalent? I haven't had
> > any issues with SATA over SAS on my LSI controller.
> > On Fri, Aug 24, 2012 at 12:19 PM, Sašo Kiselkov <skiselkov.ml at gmail.com>wrote:
> >
> >> On 08/24/2012 06:15 PM, Dan Swartzendruber wrote:
> >>> On 8/24/2012 12:08 PM, Rich wrote:
> >>>> You know, you'd think so.
> >>>>
> >>>> There's lots of opinions on SAS expanders, and the general consensus
> >>>> seems to be "if you can avoid the complication, doso".
> >>>>
> >>> The only complaints I've heard are putting SATA drives on SAS
> >>> expanders.  Even that is not very clear - lots of he said/she said
> >>> stories out there...
> >>
> >> I would generally tend to agree with the "no SATA on SAS expanders"
> >> sentiment, especially given that expanders are relatively dumb devices
> >> and so expecting them to play nicely in any kind of heavy-weight
> >> protocol translation is sort-of playing with fire. However, I've yet to
> >> see a problem with SAS-on-SAS expanders, especially considering that
> >> this allows you to easily grow storage and utilize dual-porting natively
> >> built into all SAS drives (not to speak of high-order SAS topologies,
> >> such as with LSI's SAS switches).
> >>
> >> Cheers,
> >> --
> >> Saso
> >>
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> >
> >
> >
>
>
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