Storage Update: Picking up the Pieces

Well, I have placed an order for the Norco DS-1220. I ordered it from Newegg.com as an open box item. It’s a bit of a gamble, for couple of reason. The first is because open box from Newegg means someone sent it back. It may have all of it’s parts, it may be missing some parts. Newegg will not help you out if the package is incomplete.. but it did save me $180. Newegg does offer a 15 day return policy on the item though so if it shows up and is missing some critical I can send it back and buy the non-open box version, albeit it at te $180 premium. Worth a try for $180.

The second gamble is that it’s unclear if this setup is going to work on my linux machine. About 50% of the linux related reviews say that the device doesn’t work on linux and not to bother, the other 50% says it works just fine. I’m going to put my best foot forward and upgrade my server to the most current version of Fedora and we’ll see how it goes. For the techie crowd, it appears as though the drivers for the sata card are available in the kernel but not always chosen for the default kernel is the OS. Push come to shove I may need to compile a new kernel or a driver but I’ve taken a look at the default config for the Fedora 8 kernel and it looks like the driver is chosen as a module so with any luck it will be picked up during the install. We shall see…

The key to this plan is being able to use the array that is currently built on the Thecus. The nice thing about the Thecus device is that the array is built using widely available linux software tools. Most raid devices build the array using proprietary hardware that isn’t transferable to new devices. I should be able to pop the drives out of the Thecus and into the Norco and then rebuild with very little trouble. (For an overview of Linux software RAID here is a link at TLDP.org. It’s pretty old but it’s a good start. Note: raidtab is dead and not needed.)

The only problem with this setup is the thecus uses both mdadm and Logical volume management, or lvm. I should rephrase, I’ve never used lvm so I need to sort out how to use it. The premise behind lvm is that you can create groups of storage and they can be grown and resized without damaging the data. For a RAID array this is ideal. You can start with, say, 4 100GB drives. Over time you may decide to add another drive. Without lvm you’d have to destroy the array and recreate it to add that extra storage. With lvm, you just add that new data to the group and it’s added. That is my understanding at least.. I have much reading to do.

Thankfully VMWare Fusion and Fedora 8 get along great. I have been doing much testing in the virtual world. I’m going to setup some lvm groups and see how that works and then I’m going to look into how difficult it is to make the OS recognize lvm groups made on other systems. That will be the real test. If I can get Fedora 8 to see the lvm information from the thecus I can assemble the array from that box inside the norco box and be on my way. If not…

I have also backed up the data from the array to a massive Western Digital drive. It’s a 2TB usb/firewire drive. Basically it’s an enclosure with 2 1TB drives combined using some kind of mojo. The good news; it’s big, it’s fast and the included software works well on Windows XP. The bad news: Mac support is good but not as good as it is on XP, linux support does not exist. Linux sees through the magic that the box does and doesn’t mount the drive correctly nor will it see the partitioning you have done on other machines. Suffice it to say that I did significant enough damage to my drive on my Linux machine that I had to repair on my Mac. At this moment I’m doing the file copy from the Thecus across the network the only windows machine I had in the house. Unfortunately it’s on a 100Mbit network so the transfer speed is pretty slow. What would take over night on a 1000Mbit Gigabit connection will take me 3+ days on 100Mbit. I started it Saturday evening and expect it to finish sometime on Tuesday. For the first day transfer speed seemed to be pretty slow at first but for some reason it’s sped up yesterday and things are moving along nicely. Windows does not have a resilient copy command built in like linux and the Mac does. For the most part when windows fails to copy a file it will failed the entire transfer. Not something I wanted to happen on a 1500GB+ of data. To get around this I used the only piece of Microsoft software I have ever recommended, it’s called Synctoy and it’s totally free. It’s built using .Net and is one of microsoft’s Powertoys. Basically they are simple to use utilities that perform the basic function that most other OSes can do out of the box. Anyways, it’s a great utility that will allow you to sync folder together. I think Microsoft’s intention was to use it for digital photography, syncing you memoery cards to the computer but it’s a great way to copy large amounts of files. It keeps a log of files that have failed so that you can look into why and copy them manually. The reason I’m using Windows to perform the file copy is because it’s not nearly as smart about permissions as Linux and OS X are.

One of the problems that the Thecus is having is with it’s user permissions. It seems to be throwing crap users and permissions onto the files. When copying files to my Mac the Mac was seeing all that user information and was able to parse it and keep the permissions but since the permissions it’s getting are bogus I was having a lot of trouble correcting things and regaining write access. The solution was to put the files onto the backup drive using XP which is unable to see the user information. It just disregards it and throws it out…

I’ll keep updating the post as things progress… I’ll even proof read it at some point…

Topslakr

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