Date: Wed, 18 Jul 2007 00:27:29 +0100 From: Tom Judge <tom@tomjudge.com> To: Michael Worobcuk <mail@michaelworobcuk.de> Cc: freebsd-stable@freebsd.org Subject: Re: Dell PERC5/i SAS5/5IR - RAID monitoring Message-ID: <469D5061.8060306@tomjudge.com> In-Reply-To: <4CC93356-890C-43DF-A905-0B9ABC990223@michaelworobcuk.de> References: <4CC93356-890C-43DF-A905-0B9ABC990223@michaelworobcuk.de>
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Michael Worobcuk wrote:
> Hi,
> I am trying to set up my first webserver. I bought a Dell Poweredge 860,
> provided with a SAS5/IR RAID-Controller.
> The problem is now, that I cannot find software, that monitors the state
> of my disks. I already tried megarc from the ports but all I get is a
> short answer that no adapters where found:
>
> #########################################################################
> megarc -AllAdpInfo -nolog
>
>
>
> **********************************************************************
> MEGARC MegaRAID Configuration
> Utility(FreeBSD)-1.04(03-02-2005)
> By LSI Logic Corp.,USA
>
> **********************************************************************
> [Note: For SATA-2, 4 and 6 channel controllers, please specify
> Ch=0 Id=0..15 for specifying physical drive(Ch=channel,
> Id=Target)]
>
> Type ? as command line arg for help
>
> No Adapters Found
>
> Error: No MegaRaid Found
> #########################################################################
>
> I had emails with Dell and LSI. Dell does not support FreeBSD and LSI
> says I should go and ask Dell ...
>
>
> The second thing is, the perfomance.
<<<<SNIP>>>>
> Final score for writes: 16
> Final score for reads : 2025
> #########################################################################
>
> (Just to remember: Pentium D; 2,8GHZ; 4 GB RAM; 2 x 500GB SATA RAID1)
> That is pretty poor, isn't it ?
>
>
> I am wondering now, if somebody has experience with the PERC5/I
> Controller. Would it be possible to monitor the disks, if I would buy
> that controller ?
> Any hints are highly appreciated.
>
> Thanks
>
> Michael
I don't know about monitoring the SAS5/I however I read some posts on
one of the lists that was talking about the linux compatibility system
providing all of the correct interface for the linux version of
?megacli? to work on FreeBSD. As the SAS5/I is mpt driver based could
it not be checked with camcontrol? (Just an idea never tested).
As for performance issues with the SAS5/i, there is a problem in the
controller. A work arround was created by Scott Long which created a
sysctl that could be set to cause the controller to turn on the on drive
write cache's. These changes where commited to RELENG_6 on 2007-06-05
21:32:57 UTC.
The PERC5/[ei] controllers do not suffer the performance problems of the
SAS5/i controller, we have ~30 systems with these controllers and have
never seen any performance problems with them even when they have 20
drives attached to them.
If you had search the archives you would have found an almost identical
response by me to an almost identical question regarding the SAS5/i
performance problem.
Tom
Here is the original commit log:
scottl 2007-06-03 23:13:05 UTC
FreeBSD src repository
Modified files:
sys/dev/mpt mpt.c mpt.h mpt_cam.c
Log:
mpt.c:
mpt.h:
Add support for reading extended configuration pages.
mpt_cam.c:
Do a top level topology scan on the SAS controller. If any
SATA device are discovered in this scan, send a passthrough FIS to set
the write cache. This is controllable through the following tunable at
boot:
hw.mpt.enable_sata_wc:
-1 = Do not configure, use the controller default
0 = Disable the write cache
1 = Enable the write cache
The default is -1. This tunable is just a hack and may be
deprecated in the future.
Turning on the write cache alleviates the write performance problems
with SATA that many people have observed. It is not recommend for
those who value data reliability! I cannot stress this strongly enough.
However, it is useful in certain circumstances, and it brings the
performence in line with what a generic SATA controller running under
the FreeBSD ATA driver provides (and the ATA driver has had the WC
enabled by default for years).
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