raid 5 on 2,5 inch sata hdds: 6x 5400 rpm or 4x 7200 rpm?
I have a system that serves roaming profiles through samba. The highest load this system faces is when people start leaving the office at 4pm and everybody starts sync-ing. It still works on a cheap and old hardware. X3220 and raid-1 array on mdadm and WD WD1002FBYS HDDs (SATA, 3,5 inch, 1TB, 7200 rpm, 32 mb cache). Single 1Gbit connection. The bottlenecks are: 1. the net, 2. the HDDs. The windows profile syncing are basically random RW operations from a few dozens of processes running at max network speed.
Now I have a new rig for the system. R610 dell with multiple 1GBit interfaces that can be trunked and H700 hardware raid. I'm wondering what to get into the hard drive 2,5 bays. I need at least 2 TB of space. Users will be happier with bigger quotas....
I have following options:
* 6 pcs. of 5400 rpm 1TB 2,5 inch SATA hdds to get into RAID-5
* 4 pcs. of 7200 rpm 1TB 2,5 inch SATA hdds to get into RAID-5 (there still is one model available out there...)
* what random RW speed differences to expect?
* is abandoning RAID-1 on mdadm in favour of H700 HW RAID-5 is a good idea to get bigger random RW speeds?
* if I'll use 2-4 network interfaces, will changing hdds bring any difference in reducing windows profile syncing speeds?