iscsi ramsan tests, intro

The goal is to create a so called Ram-SAN by using iSCSI and other tools on systems running Linux only.

While I have a lot of questions, to which i look answers for, i already went through several configurations, running them and collecting data to create statistics, which of course i will provide.

The idea behind it was/is to increase the lookup speed of a database, which has a lot of reads and writes. The data gets more, the local memory can not keep up in size for caching and buffering.

In any way, the focus is on lookup speed.

Some facts:

• the mean search time on hard discs today is measured in milliseconds <10ms.
• RAM access time is measured in nano seconds <100ns
• 1 second is 1000ms or 1000000000ns, so 1ns is 0.000001ms
  
• when i send a ping over an ethernet network, it has a roundtrip time of 0.1ms to 0.2ms
• 1Gbit/s is around 120MB/s
  
• packing/unpacking data to send and receive a request costs time as well
  

In any way, i will lose most of the time won by accessing RAM on sending this data over the network. On the other hand, summed up, i still win a lot on random access.

An interesting alternative these days is a flash drive. Which will also let me ranting about crash safety in general.