ou have a SSD that uses a 4 KB page and 64 pages per block. You have a record si
ID: 3573525 • Letter: O
Question
ou have a SSD that uses a 4 KB page and 64 pages per block. You have a record size of 768 bytes and a file of 100,000 records. Assuming that records do not span page boundaries, how many blocks will the file use? You have a SSD that uses a 4 KB page and 64 pages per block. If your drive size is 200 GB, how many blocks are there? With the drive as specified above, if each block can sustain 50000 flashes, what is the maximum life of the drive in block-flashes? If you are processing 100 million transactions per day, how many of those transactions will cause the record (and its page) to be relocated? This is a good argument for buffering or caching each page as long as possible. But let's continue to assume no buffering or caching so that each relocation results in a page being moved. How many blocks, at 64 pages per block, will be needed to handle these relocations each day? How many days of this activity can the drive specified above handle? Convert the answer above to years (assume 365 days per year)?
Explanation / Answer
As you have too many sub quesitons in the list, I am allowed to answer first four part of subquestion.
(1) For a record length of 768 bytes, you can put 5 records in 4 KB page. You need to store 100,000 records, therefore you need 20,000 4 KB paes. Since a block is 64 pages, then you need 312 ful blocks and half of another block. So you need 313 blocks to store this file.
(2)
1024 MB = 1 GB
1024 KB = 1 MB
1 page = 4 KB
64 pages = 64 * 4 = 256 KB per block
256 KB - 1 block
1024*1024 KB = (?) block
Blocks = 4096 in 1 GB
200 GB = 4096 * 200 = 819200 Blocks
(3) Each block can sustain with 50,000 flashes.
so we have total lifetime of 200 GB SSD = 819200 * 50000 = 40960000000 block-flashes
(4)100000000 transaction each day assuming that no caching or buffering occur, so that each transaction result in page to be moved.
As 64 pages per block, so every 64 transaction 1 block is relocated.
So that for 100000000 transaction 1562500 blocks relocated each day.
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