Bug 19129

cwilkes@singingfish.com writes:
> 
> >Number:         19129
> >Category:       misc
> >Synopsis:       AMI Raid Express 200 card extremely slow ( < 6MB/s)
> >Confidential:   no
> >Severity:       non-critical
> >Priority:       medium
> >Responsible:    freebsd-bugs
> >State:          open
> >Quarter:        
> >Keywords:       
> >Date-Required:
> >Class:          sw-bug
> >Submitter-Id:   current-users
> >Arrival-Date:   Thu Jun 08 11:30:00 PDT 2000
> >Closed-Date:
> >Last-Modified:
> >Originator:     Chris Wilkes
> >Release:        4.0
> >Organization:
> >Environment:
> FreeBSD octopus 4.0-STABLE FreeBSD 4.0-STABLE #0: Sun May 28 11:04:59 GMT 2000
> >Description:
> File server with an AMI MegaRaid Express 200 card attached to a disk enclosure
> with 8 9G LVD SCSI2 drives, for a total of ~60G of RAID5 storage.
> Disk writes are extremely slow on it, around 6MB/s.  Called AMI and they
> suggested moving from Linux to FreeBSD.  Did that and I still see the same
> (bad) performance.
I see that if LVD controller works with non-LVD disks
I dont know  AMI MegaRaid Express 200 card  - are you shure it has
LVD interface?

> Speed (MB/s)	Description
> 17.1		internal SCSI -> other internal SCSI
> 16.5		raid -> internal scsi
> 6.05		internal scsi -> raid
> 4.10		raid -> raid
> 
> The drives are rated at 20MB/s, I'm really happy with the 17.1MB/s I'm seeing
> for local to local.  I was expecting a huge gain up to about the 80MB/s max
> spec for scsi-2, but instead writes are 1/3 the speed.
> >How-To-Repeat:
> Reformated drives after the system became unstable and core dumped on an
> fsck.  Still the same performance numbers.
> >Fix:
> 
> 
> >Release-Note:
> >Audit-Trail:
> >Unformatted:
> 
> 
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> 


-- 

ZZZZ X   X
  Z   X X          ZX Spectrum software museum
 Z     X   http://www.zx.ru/    ftp://zx-museum.org.ru/
Z     X X        babolo@zx.ru  Alexandr Babaylov
ZZZZ X   X

On Fri, 9 Jun 2000, Aleksandr A. Babaylov wrote:

> > File server with an AMI MegaRaid Express 200 card attached to a disk enclosure
> > with 8 9G LVD SCSI2 drives, for a total of ~60G of RAID5 storage.
> > Disk writes are extremely slow on it, around 6MB/s.  Called AMI and they
> > suggested moving from Linux to FreeBSD.  Did that and I still see the same
> > (bad) performance.
> I see that if LVD controller works with non-LVD disks
> I dont know  AMI MegaRaid Express 200 card  - are you shure it has
> LVD interface?
> 

I painfully know that the drives are LVD as I tried to hook them up to an
Adaptec card when this was to be used with a Sun Sparc box.  Didn't work
as they do not support LVD drives.  I've since started to use this array
on my (then) Linux and now FreeBSD 4.0 one.
Also the active terminator I have specifies "HVD" "LVD" and "SE" and the
LVD light is lifted up.
As for the card, it can support SE (single ended) or LVD (low voltage
differential).  I would imagine that if it were in SE mode my terminator
would state that.
I played around with the TCQ (command tag queuing) settings in the
MegaRaid BIOS and that didn't seem to have an effect.
Changing from raid 5 to 0 caused the times to be about cut in half.  So
instead of 6MB/s it would be closer to 10MB/s -- which is still half the
speed of one of the internal SCSI drives!

Comment 3 iedowse 2001-12-02 21:19:08 UTC

State Changed
From-To: open->feedback


Does this problem still exist?

Comment 4 iedowse 2001-12-02 21:36:18 UTC

State Changed
From-To: feedback->closed


Mail to submitter bounces.