SSD drives don’t secure erase

February 23, 2011 Leave a comment

So if you’re in the industry that requires its’ drives secure erased, or even if your a security minded person.  I came across a very interesting study.

In essence it says that because there is some brains on the actual SSD itself, there is no way to be sure you’ve erased the disk.   In a normal HDD, the erase program just writes a ton of 1’s and 0’s to the disk.  The problem is when the erasing program writes to what it think is block X, the SSD might actually write to block Y.  This is because of the way SSDs try to spread out the data so that one particular area of the memory chip isn’t over utilized.

This is quite an interesting article.

http://www.usenix.org/events/fast11/tech/full_papers/Wei.pdf

Categories: Storage Tags: , ,

Inital impressions of Ubuntu 10.10

February 16, 2011 Leave a comment

Alright so even though i work in IT, i actually like Windows OS’s for a few reasons.  Granted i’m refering more towards Windows 7, Server 2008, and maybe XP.

However i’m pretty good with Linux, and i use a 2010 MacBook Pro for work, so suffice to say i’ve worked with the major players.  I recently decided to try my hands at doing a ChromeOS build, but to do so they recommend Ubuntu.  I’ve used Ubuntu in the past, but not anytime recently.  I’ve been using Fedora or CentOS, since i’m comfortable with RHEL.

I have to say i’m really really impressed with the new Ubuntu.  I think it actually could make for a very nice Full-Time OS, even for the average user.  Now granted i wouldn’t give it to the extreme novice, but for your average user, especially a power user it works quite well.  They have made it intuitive, and easy to use.  It is “pretty” which is still necessary as most people don’t want something that looks like it’s from the Windows 3.1 era.

I think i’m going to keep it as a VM for a while, yet i think i’m going to try and do as much work in it as possible.  Here’s to nothing…..

Boot from USB drive in VMware Workstation

February 16, 2011 Leave a comment

Its quite annoying that you can’t boot from a USB Drive in VMware Workstation.  So here’s a simple workaround.

1. Download PloP boot manager http://www.plop.at/en/bootmanager.html#download

2.  Extract the .ZIP

3. Attach the .ISO from the extracted .ZIP to your VM that you want to USB boot.

4. Making sure the USB stick is inserted into your PC, and attached to the VM.

5.  When the PloP boot manager comes up, select “USB”.

Enjoy booting whatever you have on your USB drive.

VMware Workstation USB Issues

February 16, 2011 1 comment

So i’m using VMware Workstation 7.1 to run Ubuntu under my standard Windows 7 desktop.  I’m trying to build ChromeOS to play around with, and i can’t get my USB stick to be seen on my VM.

As it turns out the VMware USB Arbitration Service on my host isn’t started, and in fact wont start.  Turns out there is some USB filter driver causing the issue.  I’m willing to bet it’s part of the driver for my new USB 3.0 Motherboard.

Anyway here is the simple fix.

Shut down Workstation.

Open the registry (Start > Run > regedit).

Browse to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\hcmon\.

Create a new key called Parameters.

In Parameters, create a new DWORD value entry named DisableDriverCheck, and then set the value to 1.

This works great and i can now pass USB to my VM.

Enjoy

Time settings/issues on ESXi 4.1

December 16, 2010 Leave a comment

Here are some short and sweet items that i discovered yesterday;

Interestingly, ESXi does not allow you to change the timezone, it is permanently set to UTC.

Also, If you setup an NTP server on your ESXi hosts and that NTP server goes away for some reason, the ESXi host will not revert to using its’ own clock or even continuing to make a valient effort of keeping time, it instead reverts to January 1, 0001, to say this creates some issues is simplifying it.  The ESX hosts complain about not being able to “synchronize”, which is the first clue you get about the issue.  When you try and manually set the date through the VI-Client, you get a bunch of errors when you try and do anything and then the VI-Client froze.  The only option i found was to get that NTP server online.

Note: It may have been possible to do it via powershell or cli commands, however i had needed to get the NTP servers online anyway, and once this occurred, the ESXi servers re-synced and was able to respond.

“Save Location of VMDK” Bug in Virtual Center

December 16, 2010 Leave a comment

So while doing a Proof of Concept test on a replication product for P2V, V2V and V2P scenarios a very interesting “bug” was encountered in Virtual Center that i’ve never encountered before.  We have to add .vmdk files that belong to VM “containers” to a “Master” VM.  So if you are protecting a SQL Server, you’ll have this “Master” VM’s .vmdk and the SQL VMs .vmdk attached to this VM.

The bug is this;

If you go and add another .vmdk to a VM, AFTER already choosing “attach an already existing vmdk” for a previously added vmdk, that new .vmdk will be created in the “already existing vmdk”s folder.

Since i’ve been working crazy hours, i’ll take a second to explain better.

So you have 2 VMs, they are named, “Master”, & “SQL”.  Each one is on a separate datastore in its’ own similarly named folder, which is default.  Then you go and add a 2nd vmdk to “Master” but choose to attach the vmdk from “SQL”.  Now you create another vmdk on the “Master”, however this is a new VMDK.  If you specify the location “store with the virtual machine”, it does not save the vmdk with the “Master” vmx, which is in the “Master” folder, instead it creates the new vmdk in the “SQL” folder.  This is quite interesting….

After digging around through the logs and doing some very quick testing, i found, what i believe, is the answer.  It seems that the “store with the virtual machine” is not actually returning with the location of the .vmx file, but actually returning with the location of last disk entry of the .vmx, so in this case “SQL”.

I would assume this is a simple fix by vmware, however since i have not encountered this before i’m wondering if i have just been lucky or if this is a new issue.

Categories: Uncategorized

Why the 2TB Limit in ESX 4.1

October 12, 2010 2 comments

So i was asked this question by a collegue of mine.  “Why is there still a 2TB size limit to a LUN in ESX”.   The argument was that in this day and age, and with ESX now running on a 64-bit kernel, why are we still ham-strung by this limitation?  After some consideration and thinking it was thought that maybe VMFS was the issue, but it can’t be because you can create extents and one big VMFS volume.

Well the answer is that ESX (& ESXi) are still using the SCSI-2 Standards. Yes the same SCSI-2 that was from ~1995.  The ultimate issue has to do with the way the standard addresses the “READ_CAPACITY” of the LUN.  It uses a 10-byte call for the capacity, which limits the return to a 32-bit number. (It actually is just under a 32-bit number, the last value of 0xffffffff is acutally reserved, and thus can’t be used.  This limits you to 2199023255040 bytes, which is just under the 2TB limit.

The only current work-around is extents, which are much less then ideal.

So until VMware decides to update their outdated storage methodology, we’re stuck with the 2TB limit.

Categories: Uncategorized Tags: , , , , ,