(or, the device formerly known as the ArrowPoint Content Smartâ„¢ Web switch)
Back in the heady days of the dot com boom, one needed to be able to assure you could handle a large amount of traffic for all those visitors that you just knew were coming to your web property. In order to do that, your web application needed to be able to scale, which meant load balancing amongst any number of servers. ArrowPoint was the darling of this market, founded in 1997 and scooped up by the Cisco mother ship in May 2000 for a whopping $6.1 Billion in stock. (yes, that’s billion; you know, real money) This was 491.94 times their current revenue. Obviously, Cisco wanted into this market in a big way.
So, ArrowPoint had a nice lineup of Layer 7 switches both for the big guys (the CS-800) and the not-so big (the CS-100 line). (SlashDot used a CS-100 at one point and then upgraded to a CS-800 after a DDOS killed it.)
These devices primary purpose was to distribute IP packets amongst a server farm based on whatever criteria you could think of. You could make your content rules as simple (basic IP address/any port) or as complex as you wanted (testing for existence of a specific cookie or portion of a URL on a specific domain)
After Cisco bought them, the primary change they made was turn the case their standard blue. They also added a few models with GBICs and more buffer ram on each port (CSS11155). They even added a model that used a PCMCIA Flash Disk (e.g. CSS11154-FD-AC) instead of the 2 or 4GB IDE drives that are used to hold the OS, known as the NS and the configuration and logs.
We had been using one of those first Cisco based versions (locked flash vers 4.0, operational flash 4.0) for the sell.com server farm. We were about to deploy a new load balanced app for another client, so we decided to do some refurbishing of our supply of CSSen. I picked up a couple off eBay, one of the Cisco versions and one of the older ArrowPoint versions for under $500 and started tearing them apart. These devices when they were new went for upwards of $20,000!!!
Some interesting tidbits
- We’ve seen a decent percentage of power supplies in these units fail. I’ve actually purchased older basic 8 port units off eBay merely to have spare power supplies available.
- Upgrading the RAM to the full 256MB is easy, cheap, fast and gives the CSS plenty of room to breath for packet processing.
- The IDE drives in these devices are getting fairly long in the tooth.
RAM:
There are two slots on the CSS motherboard for installed RAM. The slots are underneath (if yours has one) the daughtercard that is used for the additional ports (2 GBIC, 4 x 100FX, 4 x 100BT), so in order to upgrade the ram, you will need to pull this card out temporarily. It’s got about 3 screws and comes out without too much fuss.
The chip to use is a Micron 128MB DDR 100 MHz MT8LSDT1664HG-10EB1, so with 2 of these the CSS will have 256MB. I picked up a couple for sub $15 each.
Disk system:
The IDE drive in the non FD (Flash Disk) models is usually a Fujitsu 2, 4 or 6GB drive. The NS and logs take up a very small part of the space on these disks, so we decided to replace the only non-solid state part of the CSS (not counting the fans) with some newer, more reliable technology. I found a CompactFlash to IDE adapter for sub $20 and a 2GB CompactFlash card for about $60. I did some research into the long-term reliability and durability of CompactFlash. There are industrial-strength CF cards, but they are about 5-10 times as expensive. The major technological consideration of CF cards is the use of single-cell vs multi-cell memory. For long-term reliability, you want single-cell as the electronics on the card will actually monitor the health and adjust the storage of data within the cells as it finds problems and single-cell CF is also rated for a higher number of writes and has a higher MTBF. Good explanation here: DailyTech – Solid-state Drives Ready for Prime Time
So, with a 2GB Kingston Elite Pro “disk” installed, we merely use the Offline Diagnostic Menu accessible from the console port to format the new disk and use the boot from FTP function to pull down an updated NS (an ADI or ArrowPoint Distribution Image) onto the disk and it’s ready to start configuring.
The FD model of CSS comes with a PCMCIA to IDE sled in the place of the hard drive. Inserted into that slot is a 350MB SanDisk PCMCIA flash card. We’ve purchased the 1.2GB version of these cards and done the same process as above. Flash goodness all around.
One interesting note, I expected the see some decent amount of savings in amps when replacing an actual hard disk drive with a flash drive, but curiously, I didn’t. The device pulled about 0.92 amps (110V) with the hard drive and only went down to 0.85A with the flash drive. It’s interesting that a device of this type pulls so much current in the first place. Most of the switches we utilize typically draw in the 0.3A range or less. I guess that could be related to why we see a higher failure rate with the power supplies.
Summary
In the end, we ended up with some new/spare load balancers that have been cleaned up, upgraded and made more reliable. Not bad for a couple hundred dollars spent.