Thank you Areca! 6Gbps 1880 support in illumos
A big thank you goes out to Areca.
Areca have provided the source code for their Solaris driver, including support for the newer 6G RAID adapters. As a result, I've integrated a (somewhat cleaned up) copy this code as an update to arcmsr(7d) in illumos, under generous open source licensing:
This will make another HBA option available to folks. (Note these cards do support a JBOD mode, so you don't have to use hardware RAID -- indeed I would recommend that you don't when you have ZFS on the disks.
Areca have provided the source code for their Solaris driver, including support for the newer 6G RAID adapters. As a result, I've integrated a (somewhat cleaned up) copy this code as an update to arcmsr(7d) in illumos, under generous open source licensing:
changeset: 13305:fb26af81b9b2
tag: tip
user: Garrett D'Amore
date: Fri Mar 25 22:14:56 2011 -0700
description:
834 need support for Areca 1880 6Gbps
Reviewed by: Dan McDonald <danmcd@nexenta.com>
Reviewed by: Albert Lee <trisk@nexenta.com>
Reviewed by: Richard Lowe <richlowe@richlowe.net>
This will make another HBA option available to folks. (Note these cards do support a JBOD mode, so you don't have to use hardware RAID -- indeed I would recommend that you don't when you have ZFS on the disks.
Comments
There are other reasons to choose RAIDZ over hardware RAID, though.
1) RAIDZ has no write-hole, and thus no opportunity for silent data loss (hw RAID does unless you have a battery backup)
2) Management. RAIDZ lets the OS manage the configuration, including growing, replacing, etc. With HW RAID you are stuck using the tools the HW vendor provides, which are often suboptimal, especially for illumos or Solaris users. (And the code to manage that is often suboptimal.)
3) Portability. If your h/w RAID controller dies, you may not be able to recover your data from the drives. With RAIDZ, you can import those disks into any system that supports ZFS and keep right on plugging... no lock-in to the HBA or the HBA vendor.
4) Diagnosability/supportability. With ZFS, you have open source software and can look at what's happening there. And so can I. With hardware RAID, if bad things happen, you're at the mercy of the RAID vendor.
I had a lot of "fun" with areca raid cards (in pass through mode).
Do crash dumps now work really reliable (uadmin)
Thanks again for working on an alternative to the mpt fusion parts.
ZFS can not repair data and can not guarantee data integrity if you use a hw raid card:
http://en.wikipedia.org/wiki/ZFS#Data_Integrity