Re: megaraid/PERC

On 11/29/2011 09:09 PM, m.roth@... wrote:
>> I wouldn't waste the time with MSM - I would simply use the BIOS
>> configuration for the RAID storage which can easily look at the drives for
>> RAID configuration and load it if it can find it.

If you haveto reboot to get to your storage, might as well have skipped
the entire process of investing in something that has management.

> I believe it's the same kind of controller, so that's ok. I'm using MSM
> for the above reasons, and that the cli isn't installed.

the MegaCli is a pain to use, its the craziest bit of software I've come
across in a long long time. However, it does work and is very reliable
in its feedback.

> anything that would let me investigate what the documentation seems to
> call a "foreign RAID".

it just means the disks have raid metadata on there which does not map
to an existing radiset on your machine. You should (1) mark the disk as
bad (2) clear the metadata on there (3) mark is good again (4) pull it
into an existing raidset. Make sure you check and adjust your rebuild
rates to match what is going on with the machine, these cards have it
set to 30% resource by default.

HTH

- KB

Re: how to install standard software on systems with heterogeneous hardware?

Thomas Burns wrote:
> I've been thinking about ways to proceed if I need to set up 5
> machines with basically identical software but somewhat variable
> hardware. A simple approach would be to just set up my golden system
> and clone the disk, but the hardware differences would probably cause
> problems.

Not in my experience. I usually do a quick install on the target machine 
with a separate /boot partition and then clone everything from the 
source apart from swap and /boot. This way the target machine will have 
proper initrd with the required modules, such as storage drivers, at the 
first boot. Then boot in single mode, reconfig networking, 
modprobe.conf, fstab, hostname, etc., reboot and that's it. This assumes 
all machines are on the same arch and you don't use LVM or software RAID 
- otherwise it's more complicated then that.

Regards,
Deyan

--

-- 
Deyan Stoykov, dstoykov@...
System administrator
Computing and Information Services Center
University of Ruse

Re: megaraid/PERC

On Wednesday, November 30, 2011 06:40:44 PM Ross Walker wrote:
> I have heard of people setting their PERCs in pass-through mode and doing software RAID, or setting the
drives up as a bunch of single disk RAID0 drives and doing software RAID, so I wouldn't rule it out.

FWIW, I've done this in testing, and for a two-socket dual-core Dell PE 2850 we have here, the Linux software
RAID was substantially faster than the PERC (U320 SCSI) built-in RAID.  Speed was checked with bonnie++
while the box was normally loaded.

In both cases, CentOS 5 was the OS installed.

YMMV.

Re: megaraid/PERC

On Dec 1, 2011, at 7:52 AM, Lamar Owen wrote:

> On Wednesday, November 30, 2011 06:40:44 PM Ross Walker wrote:
>> I have heard of people setting their PERCs in pass-through mode and doing software RAID, or setting the
drives up as a bunch of single disk RAID0 drives and doing software RAID, so I wouldn't rule it out.
> 
> FWIW, I've done this in testing, and for a two-socket dual-core Dell PE 2850 we have here, the Linux
software RAID was substantially faster than the PERC (U320 SCSI) built-in RAID.  Speed was checked with
bonnie++ while the box was normally loaded.
> 
> In both cases, CentOS 5 was the OS installed.
> 
> YMMV.
----
I think the actual controller might make a difference and also details such as whether/how much write back
cache was available and also, which RAID level would likely be significant too. Almost guessing that you
were talking about a PERC 3/Di.

Craig

Re: how to install standard software on systems with heterogeneous hardware?

On Thu, Dec 1, 2011 at 6:05 AM, Deyan Stoykov <dstoykov@...> wrote:
> Thomas Burns wrote:
>> I've been thinking about ways to proceed if I need to set up 5
>> machines with basically identical software but somewhat variable
>> hardware. A simple approach would be to just set up my golden system
>> and clone the disk, but the hardware differences would probably cause
>> problems.
>
> Not in my experience. I usually do a quick install on the target machine
> with a separate /boot partition and then clone everything from the
> source apart from swap and /boot. This way the target machine will have
> proper initrd with the required modules, such as storage drivers, at the
> first boot. Then boot in single mode, reconfig networking,
> modprobe.conf, fstab, hostname, etc., reboot and that's it. This assumes
> all machines are on the same arch and you don't use LVM or software RAID
> - otherwise it's more complicated then that.

I've done that as part of a restore operation when dropping a tar
backup onto somewhat different hardware (which would seem like a
common enough operation that there would be a nicer approach...).   If
you know as much as anaconda does about hardware devices and driver
module names you can build a working initrd manually, but it may be
easier to just install on that or identical hardware and only keep the
/boot contents.  And you'll still probably need to know some things
about device naming to fix up fstab and your network configs.

--

-- 
   Les Mikesell
     lesmikesell@...

System Time - UTC and Local Time

I have installed CentOS on a VM by checking 'System Clock uses UTC' option.
Later I selected CST time zone. Now the date command shows UTC time with
CST timezone:  "Thu Dec  1 04:14:39 CST 2011".  How do I change system
clock to show CST local time? Also, more likely a dumb question but why
isn't date command showing UTC here instead of CST?

jM

Re: System Time - UTC and Local Time

On Thu, Dec 1, 2011 at 9:47 PM, Johan Martinez <jmartiee@...> wrote:

> I have installed CentOS on a VM by checking 'System Clock uses UTC' option.
> Later I selected CST time zone. Now the date command shows UTC time with
> CST timezone:  "Thu Dec  1 04:14:39 CST 2011".  How do I change system
> clock to show CST local time? Also, more likely a dumb question but why
> isn't date command showing UTC here instead of CST?
>
> jM
> _______________________________________________
> CentOS mailing list
> CentOS@...
> http://lists.centos.org/mailman/listinfo/centos
>

This will be useful to you.

http://www.linuxsa.org.au/tips/time.html

With regards,

--

-- 
*Digvijay Patankar*
Senior Research Fellow,*
*
Dept. of Civil Engineering,
Indian Institute of Science,
Bangalore - 560012*
*

Re: System Time - UTC and Local Time

On 12/01/2011 10:17 AM, Johan Martinez wrote:
> I have installed CentOS on a VM by checking 'System Clock uses UTC' option.
> Later I selected CST time zone. Now the date command shows UTC time with
> CST timezone:  "Thu Dec  1 04:14:39 CST 2011".  How do I change system
> clock to show CST local time? Also, more likely a dumb question but why
> isn't date command showing UTC here instead of CST?

you told it that the system clock is set to UTC ... it sets the time
based on that when it boots up.

But, your system clock is NOT really set to UTC, it is set to CST.  So
you lied :D

That means it is going to shift your CST value by the amount of hours
you are away from CST as a correction, since you told it that the
hardware clock is set to UTC.

What you need to do to fix it is edit "/etc/sysconfig/clock" and if
there is a UTC=true, change it to UTC=false.

_______________________________________________
CentOS mailing list
CentOS@...
http://lists.centos.org/mailman/listinfo/centos

Re: how to install standard software on systems with heterogeneous hardware?

On Thu, Dec 1, 2011 at 2:05 AM, Deyan Stoykov <dstoykov@...> wrote:
> Then boot in single mode, reconfig networking,
> modprobe.conf, fstab, hostname, etc., reboot and that's it.

This is the sort of stuff I need to automate, at least with a script.
It is fairly repetitious and I am not reliable enough to just do it by
hand and not forget something. It would be so much better if I could
just install a custom rpm. I guess I need to bite the bullet and learn
about cobbler.

>This assumes
> all machines are on the same arch and you don't use LVM

LVM is so cool, but I actually never use any of its cool features,
just get bit by the gotchas. I am mostly just setting up simple
workstations. I wish the installer made it easier to go back to the
old-fashioned way. I guess I should talk to upstream.

Thanks for all the inputs.
Dave

Re: how to install standard software on systems with heterogeneous hardware?

On 12/01/11 10:10 AM, Thomas Burns wrote:
> I wish the installer made it easier to go back to the
> old-fashioned way. I guess I should talk to upstream.

specify your partitioning scheme of choice in a kickstart file, thats 
teh easiest way.

--

-- 
john r pierce                            N 37, W 122
santa cruz ca                         mid-left coast