[olug] Promise FastTrak 100

[Nick Walter]

I wouldn't run RAID5 on anything.  But then, I'm not a fan of the
performance penalty.

Software raid is really minimal overhead.  I use software raid-10
(technically raid-0 array made of raid-1 arrays) on linux for production
servers and haven't encountered any overhead worth noticing.  Keep in
mind I do this on disk I/O or network I/O limited applications.  If you
have a CPU-limited application then you might want to think twice.

Nick Walter


On Wed, 2003-07-23 at 10:49, Matthew G. Marsh wrote:
> On Wed, 23 Jul 2003, Brandon Lederer wrote:
> 
> > I guess I am concerned about the processor overhead in a server.  Or is
> > there not that much overhead for mirroring.  I understand how striping would
> > have serious overhead.
> 
> Two points:
> 
> 1. In a SMP system you can use slow processors (I have (2) 200M Pentium
>    Pros) and not worry about overhead due to threading structures in
>    in use (unless you are using 2.1/2.2early)
> 
> 2. If your single processor is > 450M on a server what are you worried
>    about?
> 
> Note that any processor over ~200M can drive a LAN connection fully and
> still have some leftover cycles. Thus the empirical derivation above.
> 
> FWIW - PlainStripes < Mirroring < RAID5 in terms of CPU intensivity.
> 
> And I would not run RAID5 without a SMP system (I have one with a 2G
> Athlon single CPU that gasps during hard usage)
> 
> Tweedle for Deetails...
> 
> mgm
> 
> > -----Original Message-----
> > From: Brandon Lederer [mailto:brandonl at hms4emc.com]
> > Sent: Wednesday, July 23, 2003 8:26 AM
> > To: 'Jay at RebootTheUser.com'; 'Omaha Linux User Group'
> > Subject: RE: [olug] Promise FastTrak 100
> >
> >
> > So which is better?  Linux Software RAID in the kernel or the Promise
> > ATARAID TX controllers?  3ware is the only Hardware RAID for IDE?
> >
> > -----Original Message-----
> > From: Jay Swackhamer [mailto:Jay at RebootTheUser.com]
> > Sent: Wednesday, July 23, 2003 8:02 AM
> > To: Omaha Linux User Group
> > Subject: Re: [olug] Promise FastTrak 100
> >
> >
> > Yes, with the Promise ATARAID controllers, it is 95% software raid. The
> > drivers do the work, not the hardware. If you wanted to be cheap, there is
> > only a small modification needed to the regular promise ata PCI
> > controllers to make them function like the TX raid controllers.
> >
> > > I doubt I can use the devices.... I just said they exist......... but they
> > > are
> > > mirroring.  this definitely can't be software RAID like in the kernel and
> > > stuff.  That is Software RAID..   this is something different, isnt it?
> > > I
> > > did   0, none,  Nada  configuration in the OS for this RAID, so how is it
> > > software RAID?
> > --
> > Jay Swackhamer
> > Reboot The User
> > 15791 West Dodge Road
> > Suite 135
> > Omaha, NE 68118
> > (402) 933-6449
> > (402) 933-6456 Fax
> > http://www.RebootTheUser.com
> 
> Hey Jay - Your email still no likie me.... ;-}
> 
> --------------------------------------------------
> Matthew G. Marsh,  President
> Paktronix Systems LLC
> 1506 North 59th Street
> Omaha  NE  68104
> Phone: (402) 553-2288
> Email: mgm at midwestlinux.com
> WWW:  http://www.midwestlinux.com
> --------------------------------------------------
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