From: Anders Norrbring (lists_at_norrbring.se)
Date: Fri Feb 18 2005 - 15:45:23 CET
From: "Anders Norrbring" <lists@norrbring.se> Date: Fri, 18 Feb 2005 15:45:23 +0100 Message-Id: <20050218144523.EB22DDAE0@mail.the-server.net> Subject: RE: [suse-sles-e] File systems and SCSI Arrays...
> > On Wednesday, February 16, 2005 08:55 am, Anders Norrbring wrote:
> > > > On Wednesday, February 16, 2005 03:28 am, Anders Norrbring wrote:
> > > > > > On Tuesday, February 15, 2005 01:28 pm, Anders Norrbring wrote:
> > > > > > > The disk space is located on a Compaq Smart Array 3200
> > > > > > > controller. The controller takes care of everything regarding
> > > > > > > RAID, so that part doesn't load the Linux system.
> > > > > > > The system loads the driver cpqarray in initrd, everything
> > > > > > > seems fine so far.
> > > > > > >
> > > > > > > The problem is that when the file system gets a load, for
> > > > > > > example if I copy large files to the volume, it takes forever
> > > > > > > to complete and the system seems hanged. After 10-90
> > > > > > > seconds, it continues its work. If I have one window open
> > > > > > > with 'top', that too freezes during this period.
> > > > > > >
> > > > > > > Since it's SuSE SLES9, I formatted everything with reiserfs,
> > > > > > > my thinking wass that this may be the problem, but then I
> > > > > > > tried with XFS as well, just the same problem.. I'm just
> > > > > > > guessing.. If someone can clear things up, I'd be grateful..
> > > > > >
> > > > > > Anders,
> > > > > >
> > > > > > I've got a SLES9 box running on an old Compaq 6400r with a
> > > > > > SmartArray 3200 controller and I see none of the issues you are
> > > > > > having. Reiser shouldn't make a difference (although I now
> > > > > > prefer ext3...)
> > > > > >
> > > > > > If your box is a Compaq box, did you SmartStart it before
> > > > > > installing SuSE? (The choice of OS to be installed sets the
> > > > > > BIOS up correctly.)
> > > > > >
> > > > > > Also, check your boot options in grub and look for the
> > > > > > "elevator= " parameter. If it is set to "as", try changing it
> > > > > > to "cfq" or "deadline" and see what happens after a reboot.
> > > > > > (My Compaq has the parm set to "cfq"; as I understand it, RAID
> > > > > > controllers will see poorer performance if the parm is set to
> > > > > > "as".)
> > > > >
> > > > > Thanks Mark,
> > > > >
> > > > > No, this isn't in a Compaq system, so I can't use the SmartStart
> > > > > CD.. In my grub's menu.lst, I have:
> > > > >
> > > > > kernel (hd0,1)/boot/vmlinuz root=4802 vga=0x31a splash=silent
> > > > > resume=/dev/ida/c0d0p1 showopts
> > > > >
> > > > > So, there's no "elevator" at all set, perhaps that's the
> > > > > problem... I really haven't spent any time to study kernel and
> > > > > boot options, since I haven't found any documentation at all
> > > > > regarding this old SA 3200 controller. I've just moved it from an
> > > > > old Compaq server that ran W2k..
> > > > >
> > > > > I guess I need to find boot/kernel options that can have effect
> > > > > on the Smart Array, I just don't know where to start... I'll try
> > > > > to set "elevator=cfg" in my grub as well, perhaps it can do some
> > > > > good.. :)
> > > > >
> > > > > Later,
> > > > > Anders Norrbring
> > > > > Norrbring Consulting
> > > >
> > > > Anders,
> > > >
> > > > Here's the boot line from my Compaq server's SLES9 kernel grub
> > > > setup. Note that the elevator line is "cfq" not "cfg"! Our config
> > > > lines look verrry similar, but YMMV...
> > > >
> > > > Best regards,
> > > > Mark
> > > >
> > > > (hd0,1)/boot/vmlinuz root=4802 vga=0x317 selinux=0 splash=silent
> > > > resume=/dev/ida/c0d0p1 elevator=cfq showopts
> > >
> > > I looked in the kernel's Documentation directory and found out when
> > > reading cpqarray.txt and as-iosched.txt that "elevator=deadline"
> > > would be a good choice, and so it seems.. :)
> > > Now the system looks both stable and fast, I'll monitor it and
> > > provoke it with some huge file copying..
> > >
> > > Anders Norrbring
> >
> > I use elevator=deadline on my personal workstation, which has a DPT
> > 2865U3 caching RAID controller with a 4-disk RAID5 array attached. The
> > performance, especially reads, is much improved over the SUSE default
> > setting of "elevator=as".
> >
> > Before you put your server into production, might I ask if you would be
> > interested in testing the box with both "elevator=deadline" and
> > "elevator=cfq", and posting your results?
> >
> > If elevator=deadline gets you better performance without sacrificing
> > stability, I'd be keen to use that setting. But since my
> > 3200-controller-equipped server performs some very critical functions
> > 24x7x365, I'm hesitant to change the setting from the SuSE default
> > without some confirmation from the "real world" on identical hardware.
>
>
> It seems like I was wrong.. I just made a copy of 200MB data in 6 files
> from
> an IDE drive to the RAID. After just 50MB or so, the IDE activity went to
> zero, while all the drive LEDS on the array are flashing like mad. Also,
> the console appears to be "dead" or locked up during extended amounts of
> time, between 5 and 25 seconds at a time.
>
> After that, I can use console a little while, and then the lockup comes on
> again.
>
> My Smart Array 3200 is set to 50/50 read/write caching, so it shouldn't be
> as slow as the system seems to think it is.
>
> My best bet is that the cpqarray driver isn't totally healthy, but I'll
> try
> to set elevator=cfq before I go on complaining... I doubt the controller
> is
> not fully functional, it races in Windows.. I could put in another one,
> just to try.
>
> Anders Norrbring
It seems like XFS and JFS performs equally well, about 15% faster than
Reiser when copying and moving a batch of 2000+ files occupying about 1.5GB.
There are no remarkable differences between elevator=cfg and
elevator=deadline, as a matter of fact, on my system it seems like cfq is
slightly faster than deadline. However, the differences are less than a
second in all tests I've made. In my opinion that's within measuring
tolerances.
Anders Norrbring
Norrbring Consulting
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