[rescue] Agan, I seek the wisdom of the Collective ...

Phil Stracchino phil.stracchino at speakeasy.net
Fri Aug 12 18:50:08 CDT 2005

Skeezics Boondoggle wrote:
> In all these configurations (and more):
> 12-way 85Mhz SC2000E w/8 fast/narrow SCSI buses, 12x 5400RPM drives
> 4-way 125Mhz SS20 w/2 fast/wide SCSI buses, 8x 7200RPM drives
> 8-way 400Mhz E4500 w/2 FC-AL attachments, 6x 10000RPM drives
> 4-way 450Mhz E420R w/2 wide/Ultra2 SCSI buses, 8x 15000RPM drives
> I've never seen more than ~5-10MB/sec write speeds, ever, using software 
> RAID5.  Seriously.  And the 2000E and SS20 configs had Prestoserve NVRAM 
> to help with write coalescing.
> On those same configurations with software RAID0+1 you can easily get 3-4x
> the write throughput,

Yeah, I'd noticed eprformance seemed significantly slower, but hadn't
quantified it.  (Not that I wasn't expecting it to be.)

> and in all cases the DiskSuite read performance is
> pretty good, actually... but if you can't afford the increased
> cost/power/space/noise/heat of running double the drives and need to use
> RAID5, you might consider a cheap NetApp (their RAID4 and WAFL filesystem
> implementation kick major ass) or just get a hardware RAID5 controller.  
> 'Cuz the software implementation is painfully slow.

I actually have two or three hardware RAID controllers, Mylex DAC960s.
I just haven't gotten around to researching what it'd take to actually
get them working in my U30 yet.

(Don't suppose anyone would happen to *know*...?)

> I'd be very surprised if the current ODS/SDS/VolumeMgr/WTFEVER
> [0] Another Sun product that suffers from Sun Renaming Syndrome, where it
> seems that jackasses in marketing are compelled to rename the damned thing
> every three weeks

Preach it, brother.  I can NEVER keep straight what they're "currently"
calling it.

 Phil Stracchino       phil.stracchino at speakeasy.net
    Renaissance Man, Unix generalist, Perl hacker
 Mobile: 603-216-7037         Landline: 603-886-3518

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