Re: [zfs-discuss] ZFS on external iSCSI storage

2010-07-01 Thread Roy Sigurd Karlsbakk
> >The best would be to export the drives in JBOD style, one "array" per
> >drive. If you rely on the Promise RAID, it you won't be able to
> >recover from "silent" errors. I'm in the progress of moving from a
> >NexSAN RAID to a JBOD-like style just because of that (we had data
> >>corruption on the RAID, stuff the NexSAN box didn't detect, as the
> >drives didn't detect it). As this NexSAN box can't export true JBOD,
> >I export each pair of drives as a stripe, and use them in VDEVs in
> >RAIDz2s and a spare or two. While not as good as local drives, it'll
> >be >better than trusting the 'hardware' RAID on the box (which has
> >proven to be unable to detect silent errors).
> 
> Yup, we just did the same thing with our PAC storage units. Created 48
> Raid 0 stripes with 1 drive each. We originally tried 4 drives per
> Raid 0 stripe but we ran into massive performance hits.

In case someone gets across NexSAN SATABOY boxes, keep in mind that they can 
neither do JBOD nor make more than 14 RAID sets. I ended up exporting three 
drives for each RAID-0 set and then used RAIDz2 across them together with a 
spare.

Vennlige hilsener / Best regards

roy
--
Roy Sigurd Karlsbakk
(+47) 97542685
r...@karlsbakk.net
http://blogg.karlsbakk.net/
--
I all pedagogikk er det essensielt at pensum presenteres intelligibelt. Det er 
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Re: [zfs-discuss] ZFS on external iSCSI storage

2010-07-01 Thread Roy Sigurd Karlsbakk
- Original Message -
> I'm new with ZFS, but I have had good success using it with raw
> physical disks. One of my systems has access to an iSCSI storage
> target. The underlying physical array is in a propreitary disk storage
> device from Promise. So the question is, when building a OpenSolaris
> host to store its data on an external iSCSI device, is there anything
> conceptually wrong with creating a raidz pool from a group of "raw"
> LUNs carved from the iSCSI device?

The best would be to export the drives in JBOD style, one "array" per drive. If 
you rely on the Promise RAID, it you won't be able to recover from "silent" 
errors. I'm in the progress of moving from a NexSAN RAID to a JBOD-like style 
just because of that (we had data corruption on the RAID, stuff the NexSAN box 
didn't detect, as the drives didn't detect it). As this NexSAN box can't export 
true JBOD, I export each pair of drives as a stripe, and use them in VDEVs in 
RAIDz2s and a spare or two. While not as good as local drives, it'll be better 
than trusting the 'hardware' RAID on the box (which has proven to be unable to 
detect silent errors).

Vennlige hilsener / Best regards

roy
--
Roy Sigurd Karlsbakk
(+47) 97542685
r...@karlsbakk.net
http://blogg.karlsbakk.net/
--
I all pedagogikk er det essensielt at pensum presenteres intelligibelt. Det er 
et elementært imperativ for alle pedagoger å unngå eksessiv anvendelse av 
idiomer med fremmed opprinnelse. I de fleste tilfeller eksisterer adekvate og 
relevante synonymer på norsk.
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[zfs-discuss] ZFS on external iSCSI storage

2010-07-01 Thread Mark
I'm new with ZFS, but I have had good success using it with raw physical disks. 
One of my systems has access to an iSCSI storage target. The underlying 
physical array is in a propreitary disk storage device from Promise. So the 
question is, when building a OpenSolaris host to store its data on an external 
iSCSI device, is there anything conceptually wrong with creating a raidz pool 
from a group of "raw" LUNs carved from the iSCSI device?

Thanks for your advice.
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