Server 2003 Software RAID

RAID (Redundant Array of Independant/Inexpensive Disks) arrays are common in servers and high end workstations. According to Wikipedia, there are 6 official RAID levels, along with several manufacturer specific levels. RAID is available in both hardware and software offerings, with the former being the preferred. Hardware RAID utilises onboard or dedicated RAID controllers, which take the load away from the CPU. They are generally more reliable and better performing than Software RAID - which, as the name suggests, uses Software to create and manage RAID arrays.

As all of my physical and virtual servers here use Microsoft Server Operating Systems (specifically 2003), I decided to research RAID and what was avaiable to me, as my storage is in need of some tweaking. My 2 storage servers, Fileserver and Backupserver both have 4 x 250GB Samsung Spinpoint IDE drives, connected to the mainboard via cheap PCI RAID cards, which only support a handful of RAID levels. As they're not big brand offerings, I am reluctant to use them for creating RAID arrays, in case something goes horribly wrong and I lose GBs of data.

So, I turned to Software RAID and what Server 2003 offers. Microsoft's Technet site has a create article detailing all of the options available to Server Administrators:

At least, that's how I've come to understand them. More detail can be found on both the aformentioned links.

Before I started formatting my ~1TB Backupserver drives, I decided to try out the various options to see which would suit my needs best, which is to combine the 4 x 250GB drives into a larger volume. As the Backupserver keeps a weekly copy of the Fileserver data, redundancy isn't a priority, but as 2 of the 4 drives are nearing their capacity (~232GB formatted) I could do with a larger volume.

Using Microsoft's Virtual Server platform, I was able to create 8 Dynamically Expanding Disks, each of 25GB in size (a 10th of the size of the physical drives). Attaching 2 Virtual SCSI adapters to the Virtual Machine allows you to connect up to 14 drives (7 per adapter), as you can see above. I then switched the Virtual Machine back on and opened up Computer Management:

If you initialise the Disks as Dynamic ones, you can then right click on them and choose which of the available Volume options you want to go with. Above, you can see the options available on Server 2003.

I played around with the Virtual Disks, creating a Striped, Mirrored and RAID-5 array to begin with. The Striped Volume spreads the data over 2 Disks, giving you 2 x 50GB capacity. This effectively improves I/O performance, as you have 2 Disks to read/write to. The Mirrored Volume writes the data to both Disks, giving you just 1 x 25GB capacity, but if one of the Disks fails, you still have a copy of the data. The RAID-5 volume spreads the data over all of the Disks in a way that means if 1 Disk fails, the array can be rebuilt from the remaining Disks. However, if 2 Disks fail, all of the data in the array is lost. In my example, 3 x 25GB drives would give a total capacity of 50GB - one of the drives used for redundancy.

RAID isn't to be used as a backup solution, as other factors can lead to data loss - but some levels provide redundancy in the event of Disk failure and optimise uptime of the system.

To stick with the ~1TB capacity of the 4 x 250GB drives, I opted for the Spanned volume:

In my test environment, I was able to initially create the volume from 4 x 25GB drives, giving me an approximate total of 100GB - which in the Physical servers, would mean near enough 1TB unformatted within a single volume. The beauty of a Spanned volume is that it can easily be extended. So if I find that next year I'm nearing the 1TB capacity, I can chuck another 250GB (or any size) Disk into the Server and extend the Spanned volume onto the new Disk, which would result in a 1.25TB volume. The downside to this is that if 1 of the Disks in the array fails, the whole array is broken and all of the data is lost. However, as I've mentioned, the Backupserver stores a copy of the Fileserver's data, so to have complete data loss, one of the drives in both arrays would need to fail at the same time. Fingers crossed that's something I won't be experiencing.

The performance overhead of Software RAID should be non-existant, as the Spanned volume is simply extending the capacity. Software RAID5 and Mirrored options do put additional strain on the hardware though, which should be taken into consideration if you're thinking of opting for this too.

The next step is to mimic this on the Backupserver, which will require a complete format and converting of all the Disks to Dynamic, then creating the volume and copying the data from the Fileserver across. If all goes to plan, I can then do the same on the Fileserver - which will give me a single 1TB volume, allowing me to re-create the shares without worrying about running out of space anytime soon. To give you an idea of how useful it'll be:

That's 928GB formatted capacity, spread over 4 separate Disks. 444.6GB of that is free, but not all in one useful place. Combining the space into one volume would make life a lot easier. I'll let you know how it goes!

comments Posted: Thursday 5th February 2009, 18:00am
Categories: Computers and Technology, Slickhouse
Tags: microsoft, server-2003, software-raid

Server upgrade

I had planned to start a server upgrade this holiday - however due to the NTLDR is missing error message appearing during a server reboot, the upgrade was rushed forward to this afternoon.

After attempting a repair from the Server 2003 install CD (which failed), I decided to swap out the 120GB main drive for another I had lying around. Then whilst the fileserver was re-installing Server 2003, I put the dead drive into an external enclosure and attached it to the new server. Luckily the drive was still alive and I was able to copy the 50GB+ of Virtual Machines to the new server.

To cut a long story short, everything is up and running now, with my setup split across 4 servers now instead of the previous 3. You'll notice a slight speed increase from the upgrade - as the slickhouse homepage now takes around 0.5 seconds to generate, rather than the previous 0.7. I'll look into moving MS SQL Server to a new virtual server, leaving MySQL on its own to occupy the full allocated RAM, in the near future - which may reduce that time even further. The new setup is as follows:

Router:

Backupserver (not always on): Fileserver: Virtualserver: The Virtualserver itself still uses Microsoft's Virtual Server 2005, though I tried installing VMWare's ESXi, but it doesn't support the motherboard's onboard SATA controller (AMD 780G Southbridge). The point to mention is that it can support up to 16GB RAM, using 4 x 4GB modules - however 4GB DDR2 modules are still a rarity. At the moment it's using about 1/2 of the 6GB RAM running 7 virtual machines (all Server 2003 at 256/512 RAM allocation).

I've decided to stick to Virtual Server 2005 for the forseeable future, as it's very quick to get a Virtual Machine back up and running if I encounter another problem like today's. It's simply a case of copying across the vhd and either creating a new machine (pointing to said vhd), or also copying across the vmc file to keep the existing machine's settings.

Separating the 1TB storage from the virtual servers should make storage upgrades easier in the future and also allow for less downtime when carrying out maintenance. Let's see?

comments Posted: Sunday 28th December 2008, 18:00pm
Categories: Computers and Technology, Slickhouse, Web
Tags: microsoft, server-2003, virtual-server

Server 2003 permissions issue

Over the last few months I've received the following error message when trying to execute, well, executables stored on my fileserver:

Permissions1

"Windows cannot access the specified device, path, or file. You may not have the appropriate permissions to access the item."

As the message suggests, I thought it was to do with permissions, so began trying to solve it by amending permissions on the fileserver, the active directory domain server and the mailserver that this error message was appearing on. I tried everything, from logging on as different active directory users, leaving/joining the domain and re-creating the shares/permissions too. The thing that completely confused my testing was that the non-active directory users didn't see the message (such as the local administrator). Also, logging on as the same user, but on a different server yielded different results - as I was able to execute the .exe without any issues.

After several hours of trawling forum posts with similar issues, I read that some people uninstalled the Internet Explorer Enhanced Security Configuration, which seemed to solve things:

Permissions2

This is found within control panel > add/remove programs > windows components. After removing it, the error message still appeared, but I had previously read that executable files are blocked if moved from one location to another, preventing them from being used until unblocked:

Permissions3

If you right-click on the .exe and choose properties - you'll see something similar to the above. Click on unblock and you'll be able to execute the file once again!

So, what originally appeared to be a permissions error, limited to the active directory domain - turned out to be linked to Internet Explorer's Enhanced Security Configuration. I suppose in a production environment you'd trust the share(s) prior to trying to execute files on them, but even so - it just goes to show how unrelated error messages can be!

comments Posted: Sunday 21st December 2008, 18:00pm
Categories: Computers and Technology
Tags: microsoft, permissions, server-2003

The Switch Over

Over the past few weeks I've started the switch-over to a self-hosted solution for slickhouse and the other sites I maintain.

The first hurdle was leapt over with few problems - as I've now got a decent web server up and running within slickhouse itself. A full article will appear within the near future, once the software configuration has been completely tweaked. In the meantime, I can confirm it's running Windows Server 2003 R2 with IIS6; Pearl; PHP and MySQL - the latter two of which are required for WordPress.

The web server is running under within Microsoft Virtual Server 2005, with the host O/S being another 2003 install. The host machine is my upgraded Fileserver - consisting of an Athlon XP 3000 (Barton); 2GB PC3200 DDR; MSI K7N2; 120GB main drive and 4 x 250GB data drives. So far, benchmarks have proved that the setup is on par with the current machine that slickhouse is hosted (shared) on.

Although there's currently only a holding page on the web server, for [domain no longer active], it'll soon host slickhouse.com; lazlow.net and babysfirstblog.com, along with any future domains.

The server itself has been up and running for a few weeks and has already received a few hack attempts - mainly via ftp, but none have so far been successful.

Initially, I was going to be running 2 Virtual Servers in tandem - the first being Server 2003 for static sites and the second being either CentOs; Litespeed or Ubuntu Linux Server. However, as I work with Windows web servers on a day-to-day basis at work, I eventually opted for purely Server 2003. After many late nights of trying to get PHP and MySQL playing ball, I got WordPress working successfully too on IIS (more detail coming soon).

So, all that's left now is to transfer several domains that are with my current host (UKHost4U) to GoDaddy, my new domain registrar. This is where the tricky part has taken place - it's a lot of hassle to transfer a single domain from one registrar to the next; even more hassle when transferring several, with differing TLDs. I'm still awaiting slickhouse.com; slickhouse.net; lazlow.net and babysfirstblog.com to be transferred. Unfortunately, GoDaddy don't currently support the transfer of .uk domains, so I need to find an alternative way to control slickhouse.co.uk.

Once the domains are all within my control, I can then start setting up DNS for them all - via DynDNS.com. Coupled with my recent router upgrade to Smoothwall, this will allow me to host the sites from a dynamic IP. Then it's just a case of pointing the domains from their current IP to the new web server, in slickhouse.

I'll keep you updated with how the Switch Over goes. Hopefully there will be minimal downtime to the sites during the coming months. If anyone's looking to host their domain/site at slickhouse let me know, as there's plenty of space!

comments Posted: Friday 29th February 2008, 18:00pm
Categories: Computers and Technology, Slickhouse, Web
Tags: dyndns, godaddy, server-2003, ukhost4u, web-server