My notes, things I have learned, and documentation I have created.

Here are the steps I used to bring a shared disk online from within Windows 2008 R2. I was attempting to create a Microsoft Cluster within VMWare ESXi when I ran across this issue. This worked to bring the disk online and I was able to add it to the cluster I created, however I have run across some other VMWare issues preventing me from bring up the other node of the cluster. Nonetheless, here was how I brought the disk online. Apparently, this is how Windows 2008 handles all newly added shared storage.

H:\>DISKPART

Microsoft DiskPart version 6.1.7600
Copyright (C) 1999-2008 Microsoft Corporation.
On computer: VMCL01

DISKPART> LIST DISK

Disk ### Status Size Free Dyn Gpt
——– ————- ——- ——- — —
Disk 0 Online 20 GB 0 B
Disk 1 Offline 10 GB 10 GB

DISKPART> SAN POLICY=ONLINEALL

DiskPart successfully changed the SAN policy for the current operating system.

DISKPART> SELECT DISK 1

Disk 1 is now the selected disk.

DISKPART> ATTRIBUTES DISK
Current Read-only State : Yes
Read-only : Yes
Boot Disk : No
Pagefile Disk : No
Hibernation File Disk : No
Crashdump Disk : No
Clustered Disk : No

DISKPART> ATTRIBUTES DISK CLEAR READONLY

Disk attributes cleared successfully.

DISKPART> ONLINE DISK

DiskPart successfully onlined the selected disk.

DISKPART> ATTRIBUTES DISK
Current Read-only State : No
Read-only : No
Boot Disk : No
Pagefile Disk : No
Hibernation File Disk : No
Crashdump Disk : No
Clustered Disk : Yes

DISKPART> LIST DISK

Disk ### Status Size Free Dyn Gpt
——– ————- ——- ——- — —
Disk 0 Online 20 GB 0 B
* Disk 1 Online 10 GB 10 GB

I have spending quite a bit of time recently playing with Microsoft’s Office365. I have been interested in how to manage the DNS records in my linux DNS to support Office365. For example, I wanted to access my Office365 email, Lync server, and Sharepoint via my specified hostnames as defined in my DNS. Email was simple enough. Setting up these records got the email to my domain directed properly, and I was able to use auto discover to configure my iPhone, android device and desktop computer email clients easily. I have listed the key records below:

mydomain.com. 360 IN TXT “v=spf1 include:outlook.com ~all”

$ORIGIN mydomain.com.
@ IN MX 0 mydomain-com.mail.eo.outlook.com.
ms49911282 IN CNAME ps.microsoftonline.com.
autodiscover IN CNAME autodiscover.outlook.com.

Lync presented a bit more of challenge. And I found several sources on the Internet of people trying to get the records set up properly, but all of them seemed to have something wrong. Ultimately, these are the records that I had to add to access my Office365 Lync server. The lesson learned from setting these records should help records that Active Directory requires that I have never had occasion to look at before.

_sip._tls IN SRV 100 1 443 sipdir.online.lync.com.
_sipfederationtls._tcp IN SRV 100 1 5061 sipfed.online.lync.com.

Sharepoint is giving me a bit of an issue that I have been trying to address with Microsoft, but they have been less than responsive. I hope this is not how small businesses can expect to be treated by Microsoft when this product goes live. It would certainly cause me to reconsider what I otherwise think is a pretty good product. Anyway, I believe I have the records defined properly, but I cannot verify them because I am unable to enable Sharepoint Online in my domain properties or intent ( I have added a screen shot of the issue at the bottom of this post.).

My company records (Sharepoint site):
sharepoint IN CNAME mycompany.sharepoint.com.
sp IN CNAME mycompany.sharepoint.com.

My public records (public Sharepoint site):
sharepoint-pub IN CNAME ProdNet11.SharePointOnline.com.
sp-pub IN CNAME ProdNet11.SharePointOnline.com.

I will update this when, I finally hear something from Microsoft.

Here are the DNS settings as documented in Office365 for mydomain.com. This is the information Microsoft provides to help you add the appropriate records:

Update 1/10/2012:
While trying out the Lync client on my iPhone, I discovered that I was missing another DNS record to support Lync server auto-discovery. I just needed to add the following record to my DNS:

lyncdiscover IN CNAME webdir.online.lync.com.

This allowed iPhone Lync clients to use the auto detect server feature. I suspect that this was needed for other clients too, since I had to set it up manually before. I am going to try this on MacOS later to see if that works better too.

To enable ftps on my CentOS 5 server I first needed to create a self-signed certificate:

# cd /etc/pki/tls/certs
# make vsftpd.pem
umask 77 ; \
PEM1=`/bin/mktemp /tmp/openssl.XXXXXX` ; \
PEM2=`/bin/mktemp /tmp/openssl.XXXXXX` ; \
/usr/bin/openssl req -utf8 -newkey rsa:1024 -keyout $PEM1 -nodes -x509 -days 365 -out $PEM2 -set_serial 0 ; \
cat $PEM1 > vsftpd.pem ; \
echo “” >> vsftpd.pem ; \
cat $PEM2 >> vsftpd.pem ; \
rm -f $PEM1 $PEM2
Generating a 1024 bit RSA private key
……….++++++
………………..++++++
writing new private key to ‘/tmp/openssl.R27560’
—–
You are about to be asked to enter information that will be incorporated
into your certificate request.
What you are about to enter is what is called a Distinguished Name or a DN.
There are quite a few fields but you can leave some blank
For some fields there will be a default value,
If you enter ‘.’, the field will be left blank.
—–
Country Name (2 letter code) [GB]:Country
State or Province Name (full name) [Berkshire]:State
Locality Name (eg, city) [Newbury]:City
Organization Name (eg, company) [My Company Ltd]:Company
Organizational Unit Name (eg, section) []:Department
Common Name (eg, your name or your server’s hostname) []:Servername
Email Address []:Emailaddress

Copy the newly created certificate to /etc/vsftpd:

# cp -p vsftpd.pem /etc/vsftpd/

Add the following to the vsftpd.conf file:

# vi /etc/vsftpd/vsftpd.conf
…
ssl_enable=YES
rsa_cert_file=/etc/vsftpd/vsftpd.pem
…

Note: As is above, this will not allow non-anoymous users to use plain ftp. They will have to use ftps. To change this behavior, add the following to your vsftpd.conf:

force_local_data_ssl=NO

Then, restart/start vsftpd:

service vsftpd restart

Note: This worked fine from WinSCP and SmartFTP, but Filezilla gives me the following:
Error: GnuTLS error -12: A TLS fatal alert has been received.
Error: Could not connect to server

Say you happened remove a disk from your RHEL/CentOS/Fedora system and left the entry to mount a partition in the fstab and rebooted. Well, you end up at a prompt for your root password and dropped into single user mode to resolve the problem before the system can boot up. I used to be able to just mount the root partition writeable by using any number of commands including “mount /” or “mount -rw /”. However, somewhere along the line that changed and those commands would not mount the filesystem as writeable. To workaround the issue, I previously used a distribution rescue disk or booted the distribution disk into rescue mode. Then, I would edit the fstab from rescue mode:

I usually chrooted the system disk:

chroot /mnt/sysimage

And then to make the changes:

vi /etc/fstab

I knew there had to be a better, more efficient way to do this, but just never took the time to figure out what is was, until now.

If you find yourself in similar situation, and need to edit a file or make some other changes to the filesystem from single user mode, this will do the trick:

mount -w -o remount /

Then, you can edit the fstab that you forgot to before carelessly removing that hard drive.

Picked up a not so obvious way to modify the Desktop icon size on a Windows 7 machine.

Hold down the control key, and use the wheel on the mouse to change them to the desired size. I am not really sure how you would do this on a laptop, but my guess is that you would drag your finger up or down the trackpad while holding down the control key.

Today, I found myself in the awkward position of having to figure out how to bring my newly upgraded ( ESXi 4.1 to 4.1 Update 1 ) host out of Maintenance Mode using Tech Mode commands, because I did not realize that I had to upgrade the vSphere client. It was even worse, because I thought I could download the new client from the ESXi server itself (http://esxi-hostnam). Instead, the ESXi host just provides a link to the VMware site. Ooopps. My LAN DNS servers are running on the same physical host, due to lack of funding. So, this little adventure forced me to discover a few more commands to manage an ESXi host from the Tech mode command line.

First off is a command that will tell you more information than you possibly ever want to know about your ESXi host. This command will spew out hundreds of lines of information about the host.

vim-cmd hostsvc/hostsummary

I highly recommend using grep to find the information you need. For instance, I used the following command to determine whether the host was in Maintenance Mode:

vim-cmd hostsvc/hostsummary | grep -i main
inMaintenanceMode = false,

To put the host into Maintenance Mode:

vim-cmd hostsvc/maintenance_mode_enter

To take the host out of Maintenance Mode:

vim-cmd hostsvc/maintenance_mode_exit

I have written about this command before, but it seems appropriate to list it here. To display all guests:

vim-cmd vmsvc/getallvms

You can also use the following command to get a “summary” of a guest:

# vim-cmd vmsvc/get.summary 160

Again, I recommend using grep, because you get a lot of output.

# vim-cmd vmsvc/get.summary 160 | grep -i name
guestFullName = ,
hostName = ,
name = “White2”,
vmPathName = “[1TBVolume] White2/White2.vmx”,
guestFullName = “Microsoft Windows Vista (32-bit)”,

Or:

# vim-cmd vmsvc/get.summary 272 | grep -i state
runtimeState = (vim.vm.DeviceRuntimeInfo.VirtualEthernetCardRuntimeState) {
connectionState = “connected”,
powerState = “poweredOff”,
faultToleranceState = “notConfigured”,
recordReplayState = “inactive”,

getallvms will display the Vmids of all the guests. You will need these to power on your guests from Tech Mode. The following command will display whether a guest is power on or not:

# vim-cmd vmsvc/power.getstate 160
Retrieved runtime info
Powered off

Finally, to power on a guest using the Vmid from getallvms command:

# vim-cmd vmsvc/power.on 272
Powering on VM:

Furthermore, here is how you can add a new configuration from Tech Mode:

vim-cmd solo/registervm pathtovmxconfigurationfile

To remove a configuration:

vim-cmd vmsvc/unregister Vmid

To check the version:

vmware -v

Download software from VMware (The zip update file.).

Put update zip file on ESX server. I created an update directory in my datastore1 directory. I use scp from the ESXi host with Tech Support Mode enabled.

Put the host in Maintenance Mode via the vSphere Client (right mouse click on the host).

esxupdate –bundle zipfile update

Reboot

Update your vSphere client, if needed by browsing to your ESXi server name (http://esxi-host).

Take out of maintenance mode via vSphere Client.

Boot guests.

I started getting the following errors every night when the /var partition backed up on one of my CentOS 5 servers.

DUMP: read error from /dev/sda5: Input/output error: [block 4125240, ext2blk 0]: count=515655
DUMP: read error from /dev/sda5: Input/output error: [block 4125252, ext2blk 0]: count=515656
DUMP: read error from /dev/sda5: Input/output error: [sector 4125240, ext2blk 0]: count=515655
DUMP: read error from /dev/sda5: Input/output error: [sector 4125252, ext2blk 0]: count=515656
DUMP: read error from /dev/sda5: Input/output error: [sector 4125241, ext2blk 0]: count=515655
DUMP: read error from /dev/sda5: Input/output error: [sector 4125253, ext2blk 0]: count=515656
DUMP: read error from /dev/sda5: Input/output error: [sector 4125242, ext2blk 0]: count=515655
DUMP: read error from /dev/sda5: Input/output error: [sector 4125254, ext2blk 0]: count=515656
DUMP: read error from /dev/sda5: Input/output error: [sector 4125243, ext2blk 0]: count=515655
DUMP: read error from /dev/sda5: Input/output error: [sector 4125255, ext2blk 0]: count=515656
DUMP: read error from /dev/sda5: Input/output error: [sector 4125244, ext2blk 0]: count=515655
DUMP: read error from /dev/sda5: Input/output error: [sector 4125245, ext2blk 0]: count=515655
DUMP: read error from /dev/sda5: Input/output error: [sector 4125246, ext2blk 0]: count=515655
DUMP: read error from /dev/sda5: Input/output error: [sector 4125247, ext2blk 0]: count=515655

Also, I found the following kinds of message in the messages file:

May 7 02:34:37 white1 kernel: ata1.00: exception Emask 0x0 SAct 0x0 SErr 0x0 action 0x0
May 7 02:34:37 white1 kernel: ata1.00: BMDMA stat 0x24
May 7 02:34:37 white1 kernel: ata1.00: cmd c8/00:50:ea:9f:03/00:00:00:00:00/e3 tag 0 dma 40960 in
May 7 02:34:37 white1 kernel: res 51/40:00:08:a0:03/00:00:00:00:00/03 Emask 0x9 (media error)
May 7 02:34:37 white1 kernel: ata1.00: status: { DRDY ERR }
May 7 02:34:37 white1 kernel: ata1.00: error: { UNC }
May 7 02:34:37 white1 kernel: ata1.00: configured for UDMA/133
May 7 02:34:37 white1 kernel: ata1: EH complete
May 7 02:34:40 white1 kernel: ata1.00: exception Emask 0x0 SAct 0x0 SErr 0x0 action 0x0
May 7 02:34:40 white1 kernel: ata1.00: BMDMA stat 0x24
May 7 02:34:40 white1 kernel: ata1.00: cmd c8/00:50:ea:9f:03/00:00:00:00:00/e3 tag 0 dma 40960 in
May 7 02:34:40 white1 kernel: res 51/40:00:08:a0:03/00:00:00:00:00/03 Emask 0x9 (media error)
May 7 02:34:40 white1 kernel: ata1.00: status: { DRDY ERR }

From single user mode with /var dismounted, I ran the following:

# e2fsck -c /dev/sda5

I wish I had kept the output, but I know I accepted the defaults ( “Y” ) for all the prompts or which their were a couple. After it completed, I ran dump that completed without error. We will see how it goes from here. According to the man page, any bad blocks found using this command are added to the bad block inode so that they are used by any files or directories.

To scan all SCSI buses for hardware changes enter the following:

echo “- – -” >/sys/class/scsi_host/host0/scan # “dash space dash space dash space”

I did this on CentOS 5 to discover a new disk I added, but did not want to reboot the server.

Note: You might have to use one of the other host directories. In Ubuntu, I had to use host2 before the drive would show up.

On a linux DHCP server, you can add the following linke to dhcpd.conf file to display the vendor-class-identifier of DHCP clients:

set vendor-string = option vendor-class-identifier;

I added this towards the top of my configuration in both version 3 and version 4 DHCP server installations. I did notice that not all clients report the information back. For instance, some Wyse clients. You find the information in the dhcpd.leases database file on the server.