Great job permabit, can you let me know what is the status of the pending "writes" when one drive fails and the replacement is in the process of being rebuilt. If it takes 2 hours to rebuilt the failed drive, then are all write operations suspended until then. If the write operations go on then how are they striped and paritied when one drive from the raid set is missing. (assume this in raid 4,5 or 6)
In a RAID system, before rebuild starts (either because there is no spare or it must be manually started), new writes are accepted and written to one disk, but not protected against failure. The remaining data/parity disks are updated as if writes were made to all disks in the set, but one (or two, in RAID 6) don't exist.
Once rebuild has started, RAID systems generally apply full protection to new writes and updates, and the existing data is protected as the rebuild crawls the disk.
In our RAIN-EC systems, described in another video, new data is always fully protected on write, because data is protected chunk-wise -- we don't have the same concept of a fixed "RAID set". Rebuild also always commences automatically as long as there is spare capacity anywhere in the system.
Great job permabit, can you let me know what is the status of the pending "writes" when one drive fails and the replacement is in the process of being rebuilt. If it takes 2 hours to rebuilt the failed drive, then are all write operations suspended until then. If the write operations go on then how are they striped and paritied when one drive from the raid set is missing. (assume this in raid 4,5 or 6)
thanks
ajazio 2 years ago
In a RAID system, before rebuild starts (either because there is no spare or it must be manually started), new writes are accepted and written to one disk, but not protected against failure. The remaining data/parity disks are updated as if writes were made to all disks in the set, but one (or two, in RAID 6) don't exist.
Once rebuild has started, RAID systems generally apply full protection to new writes and updates, and the existing data is protected as the rebuild crawls the disk.
PermaJered 2 years ago
In our RAIN-EC systems, described in another video, new data is always fully protected on write, because data is protected chunk-wise -- we don't have the same concept of a fixed "RAID set". Rebuild also always commences automatically as long as there is spare capacity anywhere in the system.
PermaJered 2 years ago