Господа, взято это из FAQ`а Infortrend`a.We?ve come a long way since a 10 megabyte (10MB) disk drive was the size of your dishwasher and cost about $10K. That same $10K can buy you a terabyte (TB) of disk storage today, only about a million times more storage than 20 years ago. Unfortunately, that?s only the disk drives. What about all the other storage limitations you are going to run into?
If you are using SCSI technology, you are probably very familiar with the two-terabyte limitation. Infortrend?s CTO, Michael Schnapp, explains, "SCSI is limited to 32-bit LBAs, therefore, unless you increase sector size (which many hosts cannot handle), there is no way for a single LUN to exceed 2TB."
You will find that some Host Bus Adapters (HBA?s) will also have these limitations. Operating Systems can also have capacity and single disk limitations, especially older Unix O/S?s. However, at least generally speaking, new O/S?s have been tweaked to handle extremely large disks, such as Microsoft?s Windows 2000 that supports disk capacity in the petabytes (see table below).
Infortrend controllers support a single logical disk of up to two terabytes. You can have up to eight logical disks, which means a standard Eon or Sentinel RAID controller will give you up to 16TB of capacity. The only word of caution is that we recommend you use larger disks when creating very large RAIDs.
"From a performance standpoint, one should probably limit oneself to 16-20 drives per controller," stated Michael Schnapp. Too many small disks will ?bog? down the performance of the RAID array.
Extreme array sizes can also be cumbersome when attempting ?full? backups, requiring multiple tapes, extreme patience, and down time in some configurations. In other configurations, two or three days are required to completely back up a large system, and trimming those times down can be an important part of performance. Infortrend has been designing both snapshot and remote backup configurations for our controller line. These new features will be invaluable in a future where tape is just too slow.
Как я понимаю, тут говорится, что невозможно на одном массиве SCSI сделать RAID0 из пяти дисков по 500Gb. Видится будет только 2Тб, не больше. Ограничение на размер LUN`а.
Скажите, пожалуйста, как обстоят дела у FiberChannel... никак не могу найти документального подтверждения или опровержения того, что у Fiber`a и у SCSI в этом вопросе всё одинаково.
Попадалась инфа и про 32 бита и про 48 бит...
Мне важно знать могу ли я на Infortrend A24F-G2224-1-M5 и каком-либо Fiber контроллере собрать RAID5 из 24-х дисков по 500Gb и получить порядка 11Тб?
Компетентные органы уверяют, что это невозможно, я верю, но ведь вера - это то что мы имеем при отсутствии знаний...
Заранее благодарю.
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