February 28, 201412 yr I've been running unRAID since December 2013 with no issues. I have a 4TB WD Red drive as the parity drive and 2 - 4TB WD Red drives as data drives. Question: How many 4TB drives can I add before I expect to see capacity problems with the parity drive? Keep in mind I know absolutely nothing about how unRAID manages the parity drive. Dale
February 28, 201412 yr As long as the parity drive is equal or greater than your other drives, you will not see any issues. The parity drive doesn't have "capacity" to have issues with.
February 28, 201412 yr The parity drive is used to hold a computational bit based on the bits in the same location on all the other drives. If you were to look at it using a low-level sector editor, it would look like random noise.
March 1, 201412 yr 22 drives if you have the Pro license as that is the drive limit on the license. Sorry, Bob, but the NEW limit is 23 data drives ( http://lime-technology.com/registration-keys/ ) As I recall the limit is actually fixed by the underlying Linux operating system. It has provision for only 26 drives (a-z). With unRAID, one is required for the USB flashdrive with the operating system, one is reserved for the cache drive, one for the parity drive, and the remaining twenty-three can be used for data drives.
March 1, 201412 yr 22 drives if you have the Pro license as that is the drive limit on the license. Sorry, Bob, but the NEW limit is 23 data drives ( http://lime-technology.com/registration-keys/ ) As I recall the limit is actually fixed by the underlying Linux operating system. It has provision for only 26 drives (a-z). With unRAID, one is required for the USB flashdrive with the operating system, one is reserved for the cache drive, one for the parity drive, and the remaining twenty-three can be used for data drives. I see - 25 total with parity and cache - Interesting! Edit. I see an error on Basic: 3 devices (1 Parity, 3 Data) 3 = 1 + 3? Obviously a typo.
March 1, 201412 yr As I recall the limit is actually fixed by the underlying Linux operating system. It has provision for only 26 drives (a-z). With unRAID, one is required for the USB flashdrive with the operating system, one is reserved for the cache drive, one for the parity drive, and the remaining twenty-three can be used for data drives. There are reasons for the limit, but not Linux. Linux does not have a 26 drive limit. My test system is 70 drives. -bash-4.1$ ls /dev/sd* /dev/sda /dev/sdaf /dev/sdal /dev/sdar /dev/sdax /dev/sdbc /dev/sdbi /dev/sdbo /dev/sdbs2 /dev/sdh /dev/sdn /dev/sdt /dev/sdz /dev/sdaa /dev/sdag /dev/sdam /dev/sdas /dev/sday /dev/sdbd /dev/sdbj /dev/sdbp /dev/sdc /dev/sdi /dev/sdo /dev/sdu /dev/sdab /dev/sdah /dev/sdan /dev/sdat /dev/sdaz /dev/sdbe /dev/sdbk /dev/sdbq /dev/sdd /dev/sdj /dev/sdp /dev/sdv /dev/sdac /dev/sdai /dev/sdao /dev/sdau /dev/sdb /dev/sdbf /dev/sdbl /dev/sdbr /dev/sde /dev/sdk /dev/sdq /dev/sdw /dev/sdad /dev/sdaj /dev/sdap /dev/sdav /dev/sdba /dev/sdbg /dev/sdbm /dev/sdbs /dev/sdf /dev/sdl /dev/sdr /dev/sdx /dev/sdae /dev/sdak /dev/sdaq /dev/sdaw /dev/sdbb /dev/sdbh /dev/sdbn /dev/sdbs1 /dev/sdg /dev/sdm /dev/sds /dev/sdy -bash-4.1$ grep "Disk /dev/" fdisk -l Disk /dev/sdd: 4000.8 GB, 4000787030016 bytes Disk /dev/sdb: 4000.8 GB, 4000787030016 bytes Disk /dev/sdc: 4000.8 GB, 4000787030016 bytes Disk /dev/sde: 4000.8 GB, 4000787030016 bytes Disk /dev/sdf: 4000.8 GB, 4000787030016 bytes Disk /dev/sdg: 4000.8 GB, 4000787030016 bytes Disk /dev/sdh: 4000.8 GB, 4000787030016 bytes Disk /dev/sdi: 4000.8 GB, 4000787030016 bytes Disk /dev/sdj: 4000.8 GB, 4000787030016 bytes Disk /dev/sdr: 4000.8 GB, 4000787030016 bytes Disk /dev/sdl: 4000.8 GB, 4000787030016 bytes Disk /dev/sdk: 4000.8 GB, 4000787030016 bytes Disk /dev/sdm: 4000.8 GB, 4000787030016 bytes Disk /dev/sdo: 4000.8 GB, 4000787030016 bytes Disk /dev/sdn: 4000.8 GB, 4000787030016 bytes Disk /dev/sdq: 4000.8 GB, 4000787030016 bytes Disk /dev/sds: 4000.8 GB, 4000787030016 bytes Disk /dev/sdt: 4000.8 GB, 4000787030016 bytes Disk /dev/sdp: 4000.8 GB, 4000787030016 bytes Disk /dev/sdu: 4000.8 GB, 4000787030016 bytes Disk /dev/sdv: 4000.8 GB, 4000787030016 bytes Disk /dev/sdx: 4000.8 GB, 4000787030016 bytes Disk /dev/sdy: 4000.8 GB, 4000787030016 bytes Disk /dev/sdaa: 4000.8 GB, 4000787030016 bytes Disk /dev/sdab: 4000.8 GB, 4000787030016 bytes Disk /dev/sdz: 4000.8 GB, 4000787030016 bytes Disk /dev/sdw: 4000.8 GB, 4000787030016 bytes Disk /dev/sdac: 4000.8 GB, 4000787030016 bytes Disk /dev/sdad: 4000.8 GB, 4000787030016 bytes Disk /dev/sdaf: 4000.8 GB, 4000787030016 bytes Disk /dev/sdae: 4000.8 GB, 4000787030016 bytes Disk /dev/sdag: 4000.8 GB, 4000787030016 bytes Disk /dev/sdah: 4000.8 GB, 4000787030016 bytes Disk /dev/sdaj: 4000.8 GB, 4000787030016 bytes Disk /dev/sdal: 4000.8 GB, 4000787030016 bytes Disk /dev/sdak: 4000.8 GB, 4000787030016 bytes Disk /dev/sdam: 4000.8 GB, 4000787030016 bytes Disk /dev/sdao: 4000.8 GB, 4000787030016 bytes Disk /dev/sdan: 4000.8 GB, 4000787030016 bytes Disk /dev/sdar: 4000.8 GB, 4000787030016 bytes Disk /dev/sdaq: 4000.8 GB, 4000787030016 bytes Disk /dev/sdai: 4000.8 GB, 4000787030016 bytes Disk /dev/sdap: 4000.8 GB, 4000787030016 bytes Disk /dev/sdau: 4000.8 GB, 4000787030016 bytes Disk /dev/sdas: 4000.8 GB, 4000787030016 bytes Disk /dev/sdat: 4000.8 GB, 4000787030016 bytes Disk /dev/sdax: 4000.8 GB, 4000787030016 bytes Disk /dev/sdav: 4000.8 GB, 4000787030016 bytes Disk /dev/sdaw: 4000.8 GB, 4000787030016 bytes Disk /dev/sdaz: 4000.8 GB, 4000787030016 bytes Disk /dev/sday: 4000.8 GB, 4000787030016 bytes Disk /dev/sdba: 4000.8 GB, 4000787030016 bytes Disk /dev/sdbb: 4000.8 GB, 4000787030016 bytes Disk /dev/sdbd: 4000.8 GB, 4000787030016 bytes Disk /dev/sdbc: 4000.8 GB, 4000787030016 bytes Disk /dev/sdbe: 4000.8 GB, 4000787030016 bytes Disk /dev/sdbk: 4000.8 GB, 4000787030016 bytes Disk /dev/sdbh: 4000.8 GB, 4000787030016 bytes Disk /dev/sdbf: 4000.8 GB, 4000787030016 bytes Disk /dev/sdbi: 4000.8 GB, 4000787030016 bytes Disk /dev/sdbj: 4000.8 GB, 4000787030016 bytes Disk /dev/sdbg: 4000.8 GB, 4000787030016 bytes Disk /dev/sdbl: 4000.8 GB, 4000787030016 bytes Disk /dev/sdbm: 4000.8 GB, 4000787030016 bytes Disk /dev/sdbn: 4000.8 GB, 4000787030016 bytes Disk /dev/sdbo: 4000.8 GB, 4000787030016 bytes Disk /dev/sdbp: 4000.8 GB, 4000787030016 bytes Disk /dev/sdbr: 4000.8 GB, 4000787030016 bytes Disk /dev/sdbq: 4000.8 GB, 4000787030016 bytes Disk /dev/sda: 4000.8 GB, 4000787030016 bytes
March 1, 201412 yr There are reasons for the limit, but not Linux. Linux does not have a 26 drive limit. My test system is 70 drives. I stand corrected. I can remember this 26 drive limit came up before and the reason had to do with there being only 26 letters in the (English) alphabet. But it could be a result that unRAID logic only provided for the use of a single character in the drive descriptor. In any case (in my opinion), going beyoind 23 data drives is asking for trouble given that unRAID can only correct the failure of a single drive. (As the number of drives increases, the odds of two (or more) drives failing at a short period of time increases to the point where the single parity protection simply won't cut it.)
March 2, 201412 yr As I recall the limit is actually fixed by the underlying Linux operating system. It has provision for only 26 drives (a-z). With unRAID, one is required for the USB flashdrive with the operating system, one is reserved for the cache drive, one for the parity drive, and the remaining twenty-three can be used for data drives. There are reasons for the limit, but not Linux. Linux does not have a 26 drive limit. My test system is 70 drives. -bash-4.1$ ls /dev/sd* /dev/sda /dev/sdaf /dev/sdal /dev/sdar /dev/sdax /dev/sdbc /dev/sdbi /dev/sdbo /dev/sdbs2 /dev/sdh /dev/sdn /dev/sdt /dev/sdz /dev/sdaa /dev/sdag /dev/sdam /dev/sdas /dev/sday /dev/sdbd /dev/sdbj /dev/sdbp /dev/sdc /dev/sdi /dev/sdo /dev/sdu /dev/sdab /dev/sdah /dev/sdan /dev/sdat /dev/sdaz /dev/sdbe /dev/sdbk /dev/sdbq /dev/sdd /dev/sdj /dev/sdp /dev/sdv /dev/sdac /dev/sdai /dev/sdao /dev/sdau /dev/sdb /dev/sdbf /dev/sdbl /dev/sdbr /dev/sde /dev/sdk /dev/sdq /dev/sdw /dev/sdad /dev/sdaj /dev/sdap /dev/sdav /dev/sdba /dev/sdbg /dev/sdbm /dev/sdbs /dev/sdf /dev/sdl /dev/sdr /dev/sdx /dev/sdae /dev/sdak /dev/sdaq /dev/sdaw /dev/sdbb /dev/sdbh /dev/sdbn /dev/sdbs1 /dev/sdg /dev/sdm /dev/sds /dev/sdy -bash-4.1$ grep "Disk /dev/" fdisk -l Disk /dev/sdd: 4000.8 GB, 4000787030016 bytes Disk /dev/sdb: 4000.8 GB, 4000787030016 bytes Disk /dev/sdc: 4000.8 GB, 4000787030016 bytes Disk /dev/sde: 4000.8 GB, 4000787030016 bytes Disk /dev/sdf: 4000.8 GB, 4000787030016 bytes Disk /dev/sdg: 4000.8 GB, 4000787030016 bytes Disk /dev/sdh: 4000.8 GB, 4000787030016 bytes Disk /dev/sdi: 4000.8 GB, 4000787030016 bytes Disk /dev/sdj: 4000.8 GB, 4000787030016 bytes Disk /dev/sdr: 4000.8 GB, 4000787030016 bytes Disk /dev/sdl: 4000.8 GB, 4000787030016 bytes Disk /dev/sdk: 4000.8 GB, 4000787030016 bytes Disk /dev/sdm: 4000.8 GB, 4000787030016 bytes Disk /dev/sdo: 4000.8 GB, 4000787030016 bytes Disk /dev/sdn: 4000.8 GB, 4000787030016 bytes Disk /dev/sdq: 4000.8 GB, 4000787030016 bytes Disk /dev/sds: 4000.8 GB, 4000787030016 bytes Disk /dev/sdt: 4000.8 GB, 4000787030016 bytes Disk /dev/sdp: 4000.8 GB, 4000787030016 bytes Disk /dev/sdu: 4000.8 GB, 4000787030016 bytes Disk /dev/sdv: 4000.8 GB, 4000787030016 bytes Disk /dev/sdx: 4000.8 GB, 4000787030016 bytes Disk /dev/sdy: 4000.8 GB, 4000787030016 bytes Disk /dev/sdaa: 4000.8 GB, 4000787030016 bytes Disk /dev/sdab: 4000.8 GB, 4000787030016 bytes Disk /dev/sdz: 4000.8 GB, 4000787030016 bytes Disk /dev/sdw: 4000.8 GB, 4000787030016 bytes Disk /dev/sdac: 4000.8 GB, 4000787030016 bytes Disk /dev/sdad: 4000.8 GB, 4000787030016 bytes Disk /dev/sdaf: 4000.8 GB, 4000787030016 bytes Disk /dev/sdae: 4000.8 GB, 4000787030016 bytes Disk /dev/sdag: 4000.8 GB, 4000787030016 bytes Disk /dev/sdah: 4000.8 GB, 4000787030016 bytes Disk /dev/sdaj: 4000.8 GB, 4000787030016 bytes Disk /dev/sdal: 4000.8 GB, 4000787030016 bytes Disk /dev/sdak: 4000.8 GB, 4000787030016 bytes Disk /dev/sdam: 4000.8 GB, 4000787030016 bytes Disk /dev/sdao: 4000.8 GB, 4000787030016 bytes Disk /dev/sdan: 4000.8 GB, 4000787030016 bytes Disk /dev/sdar: 4000.8 GB, 4000787030016 bytes Disk /dev/sdaq: 4000.8 GB, 4000787030016 bytes Disk /dev/sdai: 4000.8 GB, 4000787030016 bytes Disk /dev/sdap: 4000.8 GB, 4000787030016 bytes Disk /dev/sdau: 4000.8 GB, 4000787030016 bytes Disk /dev/sdas: 4000.8 GB, 4000787030016 bytes Disk /dev/sdat: 4000.8 GB, 4000787030016 bytes Disk /dev/sdax: 4000.8 GB, 4000787030016 bytes Disk /dev/sdav: 4000.8 GB, 4000787030016 bytes Disk /dev/sdaw: 4000.8 GB, 4000787030016 bytes Disk /dev/sdaz: 4000.8 GB, 4000787030016 bytes Disk /dev/sday: 4000.8 GB, 4000787030016 bytes Disk /dev/sdba: 4000.8 GB, 4000787030016 bytes Disk /dev/sdbb: 4000.8 GB, 4000787030016 bytes Disk /dev/sdbd: 4000.8 GB, 4000787030016 bytes Disk /dev/sdbc: 4000.8 GB, 4000787030016 bytes Disk /dev/sdbe: 4000.8 GB, 4000787030016 bytes Disk /dev/sdbk: 4000.8 GB, 4000787030016 bytes Disk /dev/sdbh: 4000.8 GB, 4000787030016 bytes Disk /dev/sdbf: 4000.8 GB, 4000787030016 bytes Disk /dev/sdbi: 4000.8 GB, 4000787030016 bytes Disk /dev/sdbj: 4000.8 GB, 4000787030016 bytes Disk /dev/sdbg: 4000.8 GB, 4000787030016 bytes Disk /dev/sdbl: 4000.8 GB, 4000787030016 bytes Disk /dev/sdbm: 4000.8 GB, 4000787030016 bytes Disk /dev/sdbn: 4000.8 GB, 4000787030016 bytes Disk /dev/sdbo: 4000.8 GB, 4000787030016 bytes Disk /dev/sdbp: 4000.8 GB, 4000787030016 bytes Disk /dev/sdbr: 4000.8 GB, 4000787030016 bytes Disk /dev/sdbq: 4000.8 GB, 4000787030016 bytes Disk /dev/sda: 4000.8 GB, 4000787030016 bytes Wow! 70 4TB drives .... i'm impressed! Thankyou.
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