Thursday, March 13, 2008

Reviving a MaxAttach NAS 4300: Part 1

Residual Value

For this next entry I wanted to veer away from theory and practice to the experimental. From time to time broken equipment gets abandoned in my lab. I have a collection of very old and outdated servers. I always wonder if any of them is worth repairing for their residual value. I have repaired several old external USB and firewire drives but usually as an adjunct to facilitate the return of data to clients.

A Fortuitous Find

While cleaning up the lab I came across an old MaxAttach 4300. It wasn't particularly old. It came to me with 3 failed drives and a shutdown problem. It was out of warranty and the client didn't want it back. This model came equipped with (4) Maxtor 160 GB drives. Please excuse the mess around the unit in the image above, I was conducting tests and put it in the middle of my work area.

The MaxAttach series is self-healing. It uses RAID 1 on the system partition and RAID 5 on the data partition. So, if any drive fails it continues to behave and produce data as needed. It will send a warning to an alert IT manager and flash warnings on an attached monitor. However, if a second drive fails, it drops off line and refuses to boot.

The NAS had the unique problem of having had 3 drives fail along with an issue of randomly crashing. For the data recovery I was able to force all 4 drives to read to generate reasonable mirrors with only minimal failed sector reads. Each of the 3 drives suffered minor head crashes which left marks on the drives. By judiciously combining the drives and selecting stripes to eliminate the bad areas, I was able to recover all the data.

During my testing for this project, I discovered the cause of the shutdown problem. It had a faulty fan that worked intermittantly. Replacing the fan solved the random crashing problem. Luckily, the rest of the mother board was fine. The operating system was completely corrupted. So a fresh install of an OS would be required.

Inside the box

The MaxAttach 4300 series was a big upgrade from the 4100 series. The mother board included 2 network ports, a video port, a serial port, a keyboard port, a mouse port, and most surprisingly, was the inclusion of an adaptec 7899W chip on the motherboard.

This was no ordinary board. There are 3 additional pci slots available. In the factory configuration one pci slot was taken by a third network port. The processor was a standard Pentium 4 with supporting intel chipset.

Picking the OS

I was worried about support for different OS's on this system because of the proprietary chip set. Automatic installs would have a difficult time dealing this system. I debated trying to repair the Win2K OS that came with the NAS. Windows is a pain to repair. It has too many interconnected processes. There were other issues I had to address such as how to install the OS without a CD/DVD reader. My criteria for choosing the OS was simplicity and price. I wanted something that would provide the same basic functions that this NAS came with but without the cost of buying a new server OS. So, I narrowed the choices to Linux or FreeBSD.

SCSI! A Great Interface.

I attached a monitor with keyboard to the back of the NAS. Then, I attached a CD drive to one of the drive connects with a bootable CD. On power up it showed in the CMOS however, the on the boot screen it was conspicuously missing. On the other hand I was surprised to see that the modified bios included boot entries for both a SCSI CD and SCSI hard disk. This changed my whole perception on how to refurbish the NAS.

It was now clear to me that I needed to take advantage of the SCSI interface. I located all my adapters, converters and SCSI tools. I located an old SCSI CD and 18 GB SCSI drive. The SCSI CD used a 50 pin connector. I had to find the right setup to convert the 68 pin connection to 50 pin. The SCSI drive was easy as I had a 68 pin version. Now, I could select the boot to be the SCSI CD. I did make some modifications to the original design. My original design included 4 200 GB Western Digital drives. I chose this drive model based on availability and price. Since, completing the repair of the NAS, I can now source 500 GB drives for under $100. That would give 1 Terabyte of capacity. Wow! In my final setup I included 1 designated boot drive, the SCSI 18 GB, and 3 data drives, 200 GB for a 400GB server with RAID 5 redunancy.

Free NAS Operating Systems

In my search on the web I came across several options. The first was Centos Linux. Centos Linux is actually my favorite among the linux enterprise distros. The advantage of Centos was that it included all the features I needed. The disadvantage was that it would need a web based NAS manager. While available it would have taken some work to install and configure. I found 2 other interesting possibilities, Openfiler and FreeNAS.

I thought that I would be able to complete this article in one post. I had to break it up into 3 parts or would have been too long. The next part will address the remaining hardware issues and the final part will address installation of the NAS software.