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One of the big problems is the difference between the capacity curve and the access speed curve. The 22TB HDDs are 22x bigger than the 1TB drives of years ago;
by didgetmaster 4y ago
One of the big problems is the difference between the capacity curve and the access speed curve. The 22TB HDDs are 22x bigger than the 1TB drives of years ago; but they are no where near 22x faster. Speeds have increased to be sure, but they are in the range of 2x to 3x faster than old drives.
This means that the total time needed to read and/or write all the data on a given drive continues to increase. This is very important for things like backup or RAID rebuilds. Reading 50TB from a drive with 300 MB/s speed will take almost 50 hours.
- didgetmaster 4y agoAlso, some might think that this problem somehow goes away if you just move to SSDs; but it does not. The speeds are an order of magnitude faster, but the curves are very similar. A 4TB SSD is not 4x faster than a 1TB SSD.
- ckdarby 4y agoIsn't this partially solved from the software side though? It is common in my work to see read replicas of 2-3. Sometimes those replicas are split up into smaller "shards" across multiple disks even further. Restoring might be pulling from 10 different disks at the same time.