Re: Do extents impact speed?

Well logical logs are written to sequentially and read from sequentially as they are backed up. So you want alternate logical logs on seperate spindles or if the SAN will be caching the writes somewhere then you want enough cache dedicated to the logical logs that the backup thread will read from cache and not need to access the disk again. If you know where the most i/o occurs then spread that across disks to get more spindles and more disk controllers with the associated caches involved. More spindles are generally better and if you can utilise all the disk/san cache rather than have your activity only on some areas of the san and so only part of the caches used most of the time then performance will suffer. These days that if hard to do. E.g. With EMC Symettrix's you don't even know where of the disks your data is they just guarantee N i/os per second. Yeah right lilke by varying the disk layout I couldn't improve performance. Shoving all your i/o through one disk will be slower than spreading the i/o across controllers/disks/caches/sans. Parallel CPU processing is faster Parallel i/o processing is faster. That's my take on it. Some people throw enough hardware power at it that is does not matter until your data volumes increase.