Dell POWEREDGE RADI H700 Technical Manual

Also see for PERC H700: User guide Installation and Removal Instructions

Dell POWEREDGE RADI H700 Technical Manual Manual pdf 27 page image

DellDELL PERC H700 and H800 Technical Guide 27Figure 9. Example of RAID 50 (5 + 0)Advantages of RAID 50 Allows creation of largest RAID groups, up to 256 drives (theoretical; large RAID volumes areallowed for up to 192 drives connected to PERC H800) High read transaction rate Higher degree of fault tolerance due to parity calculation being done for each RAID 5 subset Potential for faster read transaction rates over large RAID 5 virtual disks Medium-to-high write transaction rateDisadvantages of RAID 50 Disk failure has a medium impact on throughput One of the more complex RAID implementations Less space efficient than RAID 5 since separate parity calculations are done for each RAID 5subset Retrieval of parity information after a drive failure takes longer than using a mirrored solution5.3.7 RAID 60 (Striping Across RAID 6)RAID 60 is striping over more than one span of physical disks that are configured as a RAID 6. TheRAID 6 subset must have at least four disks. For example, a RAID 6 disk group that is implementedwith four physical disks and then continues on with a disk group of four more physical disks would bea RAID 60. See Figure 10.RAID 60 stripes data across each RAID 6 subset. RAID 60 provides a higher degree of fault tolerancesince 2 drives per RAID 6 set may fail without data being lost. A performance increase over RAID 6may be realized depending on the configuration due to fewer disks reads per parity calculation.For example, if a comparison of a RAID 6 virtual disk with 8 disks were made to a RAID 60 virtual diskwith two 4 disk RAID 6 virtual disks, the parity calculation on the RAID 10 virtual disk would requirereading all 6 disks each time, where the parity calculation on the RAID 60 may require only reading4. This may vary depending on several factors such as cache and data block sizes.Drive 1 Drive 2 Drive 3 Drive 4 Drive 5 Drive 6ParityGenerationData 1 0 parity0 parity2 parity1 parity0 parity0 parity2 parity1 parityParityGenerationRAID 0RAID 5 RAID 5Data 2 Data 3 Data 4Data 5 Data 6 Data 7 Data 8Data9 Data 10 Data 11 Data 12

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