[Sunhelp] UE 220R & Solaris Questions

[James Lockwood]

On Fri, 21 Apr 2000, Pavane, Brian wrote:

> Can someone please answer the following questions for me about the Ultra
> Enterprise 220R?
> 
> - What type of SCSI connector is provided for the external interface?

HD68, Ultra/Wide.  40MB/s.  Note that this is a different SCSI bus from
the one used to run the internal drives.

> - What software is recommended for doing a Software RAID solution?

Online Disksuite (comes with Solaris) or Veritas Volume Manager (extra
cost add-on).

> - How much performance would I actually receive using a RAID card over a
> software RAID solution?  And what RAID card would you recommend?

Depends on what kind of RAID and what kind of bandwidth.  For
straightforward RAID 0 or 1 or 1+0 (combinations of striping and
mirroring) you will see little performance improvement except for write
acceleration from card NVRAM.  This is usually the most significant for
applications which require synchronous commits of many small write
requests.  For RAID 5 you can see a very large improvement, especially in
write requests. 

What is your goal?  Cost, speed or reliability?  Read mostly, write mostly
or mixed?  Small I/O bursts or large reads and writes?  There is no one
size fits all solution.

If any Sun people are listening, I'd love to hear an answer to my question
posed 9 months ago on comp.unix.solaris:

http://www.deja.com/threadmsg_ct.xp?AN=500369797

Basically, Disksuite is single threaded with regards to a single
metadevice and is a CPU pig even for regular RAID 0.  This isn't too
noticable on an Ultra-class system but really hurts on a SMP SS20. 
Disksuite cut my throughput by a factor of 3 for large I/O requests
striped over 12 disks (56MB/s to 19MB/s on a SS20/712 with 3 f/w
channels). 

-James