• RAID0 - striping
• RAID1 - mirror
• RAID5
  • do not use
  • very slow write
  • rebuild takes days, and during rebuild another disk may fail = fatal
• RAID6 - striping with double parity (5+2, 13+2).
  • minimum 4 disks
  • allow 2 disk failure
  • slower write than RAID5 (requires udpate parity on 2 disks)

Recommended levels for safety:

• RAID10 = RAID 1 + 0 = i.e two mirrors (RAID1) stripped as RAID0
• RAID6
• RAID60 = RAID 6 + 0 - two RAID6 sets stripped as RAID0

• controllers where RAID can be disabled, and all disks are exposed to host are called: HBA, JBOD, IT-MODE
  • H200
  • H310 ???
  • PERC 6 (no i letter)

• SAS1 - 3Gbps
  • SAS5E
    • SFF-8470 connector
    • supported by MD3000 (the same SFF-8470 connector)
  • SAS6E
    • SFF-8088 connector

• PERC 6
  • no memory
  • only JBOD, RAID0, RAID1
  • disks exposed to host
• PERC 6i
  • memory
  • 3Gbps connector, requires such midplane
  • no possibility to expose disks directly to host (trick is to create one RAID0 per disk)
• PERC 6iR (PERC 6 I/R)
• H series - SAS2 - 6Gbps - different connectors comparing to SAS1
• PERC H700
  • SAS2
  • SSD support
  • battery option
  • memory slot
  • must be inserter into dedicated PCI RAID slot
  • no possibility to expose disks directly to host (trick is to create one RAID0 per disk)
• H200
  • plain HBA
  • no raid
  • JBOD - all disks exposed to host (so called IT-mode)
• H310
  • plain HBA
• H330
  • 8 internal ports
  • can be flashed into HBA Flash/Crossflash DELL H330 RAID Card to HBA330/12Gbps HBA IT Firmware

H310/H710/H710P/H810 Mini & Full Size IT Crossflashing