disabling boot devices on poweredge servers?

Chandrasekhar_R at Dell.com Chandrasekhar_R at Dell.com
Wed May 5 11:52:09 CDT 2010


Hi Alex,

The command mentioned Mahaveer below is available on OMSA 6.2 release or
later.
omconfig chassis biossetup attribute=bootorder
sequence=<aliasname1,aliasname2,......aliasnameN>

To view the available aliasnames and current sequence, use the following
command: omreport chassis biossetup attribute=bootorder

You need to mention the set of aliasnames which needs to be enabled in
that sequence and rest of the devices (which you have not mentioned in
the sequence) will get disabled.

Hope this helps you.

Chandrasekhar R
Dell | OpenManage


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Today's Topics:

   1. disabling boot devices on poweredge servers? (Alexander Dupuy)
   2. deleting file takes longer than creating it (John G. Heim)
   3. Re: PE2950, LSI SAS -> SATA very slow (Adam Nielsen)
   4. RE: disabling boot devices on poweredge servers?
      (Mahaveer_M at Dell.com)
   5. Re: disabling boot devices on poweredge servers? (Adam Nielsen)
   6. Re: deleting file takes longer than creating it (Andrew Reid)
   7. Re: deleting file takes longer than creating it (Stroller)
   8. Re: deleting file takes longer than creating it (Michael Tiernan)


----------------------------------------------------------------------

Message: 1
Date: Tue, 04 May 2010 18:22:27 -0400
From: Alexander Dupuy <alex.dupuy at mac.com>
Subject: disabling boot devices on poweredge servers?
To: linux-poweredge at dell.com
Message-ID: <4BE09E23.8010409 at mac.com>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed

The syscfg utility provides a mechanism to change the default boot 
order, but I would like (for security reasons) to disable boot from USB 
or CD-ROM (I can turn off PXE boot from the NICs).  I don't want to use 
a BIOS system password (as these are servers and need to be able to 
reboot unattended) but will enable a BIOS setup password to lock in the 
changes once they are set.

I can see how to disable boot devices in the F2 setup screen, but would 
like a way to do this programmatically, without running Expect on a 
DRAC/BMC serial console session.

Any suggestions?  Is this possible using OMSA?

@alex

-- 
mailto:alex.dupuy at mac.com



------------------------------

Message: 2
Date: Tue, 4 May 2010 17:25:34 -0500
From: "John G. Heim" <jheim at math.wisc.edu>
Subject: deleting file takes longer than creating it
To: "linux-poweredge" <linux-poweredge at lists.us.dell.com>
Message-ID: <5C240731D50E4DA68553375CB1DF90C4 at math.wisc.edu>
Content-Type: text/plain; format=flowed; charset="iso-8859-1";
	reply-type=original

I have  a Poweredge SE1435 which seems to be very slow and i noticed 
something odd... I can create a large file with dd faster than I can
delete 
it.

# date; dd if=/dev/zero  of=zero.txt bs=1024 count=1000000; date; rm 
zero.txt; date
Tue May  4 16:59:21 CDT 2010
1000000+0 records in
1000000+0 records out
1024000000 bytes (1.0 GB) copied, 11.7291 s, 87.3 MB/s
Tue May  4 16:59:33 CDT 2010
Tue May  4 17:00:09 CDT 2010

It took 12 seconds to create the file and 33 seconds to rm it. Why would

that be?

This machine is serving as a print server, debian package mirror, and a 
mmysql database server. I am not sure what kind of info you might need
to 
help me. But for starters, I'm running debian lenny with a 2.6.30
kernel. 
The file system is ext3.  There are 2 500 Gb disks in the machine
configured 
as RAID-1. Here is the output from 'omreport storage vdisk controller=0'
and 
'omreport storage pdisk controller=0' ...

Virtual Disk 0 on Controller SAS 5/iR Adapter (Embedded)

Controller SAS 5/iR Adapter (Embedded)
ID                  : 0
Status              : Ok
Name                : Virtual Disk 0
State               : Ready
Progress            : Not Applicable
Layout              : RAID-1
Size                : 465.66 GB (499999834112 bytes)
Device Name         : /dev/sda
Bus Protocol        : SATA
Media               : HDD
Read Policy         : No Read Ahead
Write Policy        : Write Through
Cache Policy        : Not Applicable
Stripe Element Size : Not Applicable

List of Physical Disks on Controller SAS 5/iR Adapter (Embedded)

Controller SAS 5/iR Adapter (Embedded)
ID                        : 0:0
Status                    : Ok
Name                      : Physical Disk 0:0
State                     : Online
Failure Predicted         : No
Progress                  : Not Applicable
Bus Protocol              : SATA
Media                     : HDD
Capacity                  : 465.66 GB (499999834112 bytes)
Used RAID Disk Space      : 465.66 GB (499999834112 bytes)
Available RAID Disk Space : 0.00 GB (0 bytes)
Hot Spare                 : No
Vendor ID                 : DELL
Product ID                : HDS725050KLA360
Revision                  : K2AOAB5A
Serial No.                : KRVN67ZBGXVEVFGXVEVF
Negotiated Speed          : Not Available
Capable Speed             : Not Available
Manufacture Day           : Not Available
Manufacture Week          : Not Available
Manufacture Year          : Not Available
SAS Address               : 1221000000000000

ID                        : 0:1
Status                    : Ok
Name                      : Physical Disk 0:1
State                     : Online
Failure Predicted         : No
Progress                  : Not Applicable
Bus Protocol              : SATA
Media                     : HDD
Capacity                  : 465.66 GB (499999834112 bytes)
Used RAID Disk Space      : 465.66 GB (499999834112 bytes)
Available RAID Disk Space : 0.00 GB (0 bytes)
Hot Spare                 : No
Vendor ID                 : DELL
Product ID                : HDS725050KLA360
Revision                  : K2AOAB5A
Serial No.                : KRVN67ZBGXT2BFGXT2BF
Negotiated Speed          : Not Available
Capable Speed             : Not Available
Manufacture Day           : Not Available
Manufacture Week          : Not Available
Manufacture Year          : Not Available
SAS Address               : 1221000001000000




------------------------------

Message: 3
Date: Wed, 05 May 2010 10:57:39 +1000
From: Adam Nielsen <adam.nielsen at uq.edu.au>
Subject: Re: PE2950, LSI SAS -> SATA very slow
To: linux-poweredge at dell.com
Message-ID: <4BE0C283.9080500 at uq.edu.au>
Content-Type: text/plain; charset=UTF-8; format=flowed

>>> 10MB/sec does seem extremely poor. we've had read slowness when
Linux block
>>> device read-ahead was too small. Once properly configured,
performance on
>>> RAID-5 went from 150MB/sec to 500MB/sec, so the difference is
dramatic. we
>>> usually tune read-ahead (in Linux) buffers starting from 8MB to 32MB
and
>>> benchmark to see what works best. but your problem may be
elsewhere... we've
>>> never seen 10MB/sec...
>> Have you got any pointers to where this can be adjusted?  It seems 
>> (according to Google) there are countless methods and patches, most
of 
>> which are for rather old kernel versions.
> 
> man blockdev
> blockdev --setra blocks /dev/sda
> 
> It is part of util-linux-ng .

Thanks for the hint!  This didn't make much difference for us, but 
that's probably because the array is RAID-1, so the array readahead 
already matched the individual disk readahead.  Strangely enough 
increasing the readahead actually reduced the raw speed according to 
hdparm -t, which I wouldn't have thought would make a difference.

What did make a huge difference is setting the NCQ depth to 1 (instead 
of the default 64) as Tim suggested.  This brought raw read speed up 
from ~50MB/sec to almost 90MB/sec!

Haven't yet had the machine under a large load so will be interesting to

see how it copes, but now I really want the updated firmware from Dell!

Cheers,
Adam.



------------------------------

Message: 4
Date: Wed, 5 May 2010 09:47:29 +0530
From: <Mahaveer_M at Dell.com>
Subject: RE: disabling boot devices on poweredge servers?
To: <alex.dupuy at mac.com>, <linux-poweredge at lists.us.dell.com>
Message-ID:
	
<B35126CE4EFDD04D808637B5BE2A6AB003E33743 at blrx3m06.blr.amer.dell.com>
Content-Type: text/plain;	charset="us-ascii"

Check the OMSA command 
omconfig chassis biossetup attribute=bootorder sequence=<list>

The sequence of boot devices will be enabled in the bios and the devices
that are not part of the sequence will be disabled.

-----Original Message-----
From: linux-poweredge-bounces at dell.com
[mailto:linux-poweredge-bounces at dell.com] On Behalf Of Alexander Dupuy
Sent: Wednesday, May 05, 2010 3:52 AM
To: linux-poweredge-Lists
Subject: disabling boot devices on poweredge servers?

The syscfg utility provides a mechanism to change the default boot 
order, but I would like (for security reasons) to disable boot from USB 
or CD-ROM (I can turn off PXE boot from the NICs).  I don't want to use 
a BIOS system password (as these are servers and need to be able to 
reboot unattended) but will enable a BIOS setup password to lock in the 
changes once they are set.

I can see how to disable boot devices in the F2 setup screen, but would 
like a way to do this programmatically, without running Expect on a 
DRAC/BMC serial console session.

Any suggestions?  Is this possible using OMSA?

@alex

-- 
mailto:alex.dupuy at mac.com

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------------------------------

Message: 5
Date: Wed, 05 May 2010 14:46:07 +1000
From: Adam Nielsen <adam.nielsen at uq.edu.au>
Subject: Re: disabling boot devices on poweredge servers?
To: linux-poweredge at dell.com
Message-ID: <4BE0F80F.5000806 at uq.edu.au>
Content-Type: text/plain; charset=UTF-8; format=flowed

> I would like (for security reasons) to disable boot from USB 
> or CD-ROM (I can turn off PXE boot from the NICs).  I don't want to
use 
> a BIOS system password (as these are servers and need to be able to 
> reboot unattended) but will enable a BIOS setup password to lock in
the 
> changes once they are set.

Don't forget that anyone with physical access to the machine can do a 
BIOS reset to get rid of your password, so don't consider this as 
anything other than a deterrent!

Cheers,
Adam.



------------------------------

Message: 6
Date: Wed, 05 May 2010 10:33:33 -0300
From: Andrew Reid <AndrewReid at eastlink.ca>
Subject: Re: deleting file takes longer than creating it
To: "John G. Heim" <jheim at math.wisc.edu>,	linux-poweredge
	<linux-poweredge at lists.us.dell.com>
Message-ID: <4BE173AD.80305 at eastlink.ca>
Content-Type: text/plain; CHARSET=US-ASCII; format=flowed

John G. Heim wrote:
> I have  a Poweredge SE1435 which seems to be very slow and i noticed 
> something odd... I can create a large file with dd faster than I can
delete 
> it.
> 
> # date; dd if=/dev/zero  of=zero.txt bs=1024 count=1000000; date; rm 
> zero.txt; date
> Tue May  4 16:59:21 CDT 2010
> 1000000+0 records in
> 1000000+0 records out
> 1024000000 bytes (1.0 GB) copied, 11.7291 s, 87.3 MB/s
> Tue May  4 16:59:33 CDT 2010
> Tue May  4 17:00:09 CDT 2010
> 
> It took 12 seconds to create the file and 33 seconds to rm it. Why
would 
> that be?


At the risk of telling you things you already know, are you sure it 
really takes longer.

File deletion times vary with filesystem type; search for benchmarks on 
ext3, ext4 and xfs. Search for tuning guides for your specific
filesystem.

But first make sure you are solving a "real" problem, try this test:

dd if=/dev/zero of=zero.txt bs=1024 count=1000000; sync; echo 3 > 
/proc/sys/vm/drop_caches ; sleep 15 ; time rm /opt/tmp/ZZ;



------------------------------

Message: 7
Date: Wed, 5 May 2010 14:55:05 +0100
From: Stroller <stroller at stellar.eclipse.co.uk>
Subject: Re: deleting file takes longer than creating it
To: linux-poweredge <linux-poweredge at lists.us.dell.com>
Message-ID:
	<EE9C1314-BEEA-42E2-B4E9-CD1C80997ED6 at stellar.eclipse.co.uk>
Content-Type: text/plain; charset=US-ASCII; format=flowed; delsp=yes


On 4 May 2010, at 23:25, John G. Heim wrote:

> I have  a Poweredge SE1435 which seems to be very slow and i noticed
> something odd... I can create a large file with dd faster than I can  
> delete
> it.
>
> # date; dd if=/dev/zero  of=zero.txt bs=1024 count=1000000; date; rm
> zero.txt; date
> Tue May  4 16:59:21 CDT 2010
> 1000000+0 records in
> 1000000+0 records out
> 1024000000 bytes (1.0 GB) copied, 11.7291 s, 87.3 MB/s
> Tue May  4 16:59:33 CDT 2010
> Tue May  4 17:00:09 CDT 2010
>
> It took 12 seconds to create the file and 33 seconds to rm it. Why  
> would
> that be?

Ou of curiosity, is there a reason you didn't do
  `time dd if=/dev/zero of=zero.txt bs=1024 count=1000000 && time rm  
zero.txt` ?

> This machine is serving as a print server, debian package mirror,  
> and a
> mmysql database server. I am not sure what kind of info you might  
> need to
> help me. But for starters, I'm running debian lenny with a 2.6.30  
> kernel.
> The file system is ext3.

I'm not saying this is wholly the reason, but ext3 is notoriously slow  
at deletions.

MythTV even had (has?) a special function to accommodate ext3,  
otherwise the deletion of a movie (which might well be several gigs in  
size) would lock the system solid for a minute or two, halting  
playback and corrupting any recordings in progress. See the  
"Filesystems" section at [1].

You may not be in a position to do this, but it would be interesting  
to upgrade the filesystem to ext4 with extents, then try again. I have  
found - only in typical use, no scientific testing - the delete  
performance between ext3 and ext4 to be *very* obvious.

Stroller.



[1] http://www.mythtv.org/docs/mythtv-HOWTO-3.html



------------------------------

Message: 8
Date: Wed, 05 May 2010 09:59:25 -0400
From: Michael Tiernan <mtiernan at mit.edu>
Subject: Re: deleting file takes longer than creating it
To: "John G. Heim" <jheim at math.wisc.edu>
Cc: linux-poweredge <linux-poweredge at lists.us.dell.com>
Message-ID: <4BE179BD.2020707 at mit.edu>
Content-Type: text/plain; charset="iso-8859-1"

On 5/4/10 6:25 PM, John G. Heim wrote:
> It took 12 seconds to create the file and 33 seconds to rm it. Why
would
> that be?
>    
Because you took 12 seconds to fill a 1Kx1E6 file with bytes in the 
first instance and 33 seconds to mark the file as deleted and free all 
the blocks it took on the file system.

Filling it requires moving 1Kx1E6 bytes and deleting it requires 
changing < ~1K bytes.

No surprise here.

-- 
   <<  MCT>>    Michael C Tiernan.   xmpp:mtiernan at mit.edu
   MIT - Laboratory for Nuclear Science - http://www.lns.mit.edu
   High Perf Research Computing Facility at The Bates Linear Accelerator
   "Bit-smashing your bits better than anyone can!"


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