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hw:server:raid [2021/04/08 14:38] niziakhw:server:raid [2023/02/05 20:21] niziak
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 +====== RAID ======
 +  * 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
 +
 ====== Raid controllers ====== ====== Raid controllers ======
   * controllers where RAID can be disabled, and all disks are exposed to host are called: ''HBA'', ''JBOD'', ''IT-MODE''   * controllers where RAID can be disabled, and all disks are exposed to host are called: ''HBA'', ''JBOD'', ''IT-MODE''
Line 7: Line 24:
 ===== Dell ===== ===== Dell =====
  
-  * SAS6 
  
   * SAS1 - 3Gbps   * SAS1 - 3Gbps
 +    * SAS5E
 +      * SFF-8470 connector
 +      * supported by MD3000 (the same  SFF-8470 connector)
 +    * SAS6E
 +      * SFF-8088 connector
 +
     * PERC 6     * PERC 6
       * no memory       * no memory
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       * no possibility to expose disks directly to host (trick is to create one RAID0 per disk)       * no possibility to expose disks directly to host (trick is to create one RAID0 per disk)
     * **H200**     * **H200**
-      * plain HBA+      * **plain HBA**
       * no raid       * no raid
       * JBOD - all disks exposed to host (so called IT-mode)       * JBOD - all disks exposed to host (so called IT-mode)
     * H310     * H310
-      * plain HBA+      * **plain HBA** 
 +    * H330 
 +      * 8 internal ports 
 +      * can be flashed into HBA [[https://forums.servethehome.com/index.php?threads/flash-crossflash-dell-h330-raid-card-to-hba330-12gbps-hba-it-firmware.25498/|Flash/Crossflash DELL H330 RAID Card to HBA330/12Gbps HBA IT Firmware]]