Test I/O performance with dd

Test I/O performance by timing the writing of 100Mb to disk

Write 200 blocks of 512k to a dummy file with dd, timing the result. The is useful as a quick test to compare the performance of different file systems.

Sample Output:

Managing USB flash drives

Flipping back and forth between versions of ESXi, FreeNAS, etc means a great deal of USB flash drive management.  Luckily Windows 7 native ‘diskpart’ tool can handle wiping the USB device for those bizarre times you just want to put files on the USB flash drive.  Weird right?
Run cmd.exe as administrator
  1. DiskPart
  2. List Disk
  3. Select Disk #
  4. Clean
  5. Create Partition Primary
  6. Active
  7. Format fs=FAT32 quick
  8. Assign

Recovering from fsck.ext3 Unable to resolve LABEL problem

I was a little more than hasty in physically removing an SSD drive from my CentOS NAS box. Yes, I at least powered the system off before yanking it out.  I simply did it in the wrong order. How was I to know that the system would see ANY drive as an important drive and force you into maintenance mode even if the volume is empty.  Either way, always remove the fstab entries first when planning drive maintenance like this.

CentOS (5.7) booted up until it found the missing SSD then allowed forced me into the ‘maintenance’ console. This puts the system in to read-only mode. Meaning I could not simply edit fstab and remove the entry for my now missing drive.

Just needed to remount in read-write mode, edit fstab and move on.

A google search found this site which would have probably worked for a similar scenario where the outage wasn’t planned:  http://centoshacker.com/admin/disks/surviving-fsckext3-unable-to-resolve-label-problem.html

Forgotten password workaround Win7/Win2k8

Have you ever had a VM sit in your repository so long that you forgot the Administrator password?  Neither have I and that’s why I didn’t have to look up these steps…(borrowed from a Microsoft forum).

Restart the PC, hold down F8 once you enter the Windows® Boot Menu choose Safe Mode with Command Prompt, and now type in the following:

The first command adds a new user called “root”, the second command adds that user to the Administrators group and the third command removes the user from the Users group which leaves him in the Administrators group.

Once you have logged in as your “root” user you can then change the Administrator password, or keep logging in as “root” which seems more natural for some of us.