1. Assume that we start with no relevant data in the buffer in main-memory, and the...
1. Assume that we start with no relevant data in the buffer in main-memory, and the database system reads a data item, updates it, and writes it back to disk. Assume the data item fits in one disk block.
(a) How may disk reads and writes would a RAID-5 storage system have to perform to implement this? Explain.
(b) How may disk reads and writes would a RAID-1 storage system have to perform to implement this? Explain.
(c) Having calculated the cost for RAID-1 and RAID-5, explain whether the RAID alternative with the fewer input/output operations is necessarily the better design choice.
Homework Answers
RAID level 5, block-interleaved distributed parity, improves on
level 4 by partitioning data and
parity among all N + 1 disks, instead of storing data in N disks
and parity in one disk. In level 5,
all disks can participate in satisfying read requests, unlike RAID
level 4, where the parity disk
cannot participate, so level 5 increases the total number of
requests that can be met in a given
amount of time. For each set of N logical blocks, one of the disks
stores the parity, and the other
N disks store the blocks.
Add Answer to:
1. Assume that we start with no relevant data in the buffer in
main-memory, and the...
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Homework 13: In a file system using metadata journaling for crash consistency, what would the sequence...
Homework 13:
In a file system using metadata journaling for
crash consistency, what would the sequence of write operations be
to disk to create “file100” in the directory structure in Homework
11?
How would it differ from that of data journaling? Using the same
format as for Homework 12, identify what data or metadata is
written and where it is being written.
Format of HW12 Journal Write: Transaction Begin(TxB) record,
file X data
1.
2.
3.
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Homework 13:
In a file system using metadata journaling for
crash consistency, what would the sequence of write operations be
to disk to create “file100” in the directory structure in Homework
11?
How would it differ from that of data journaling? Using the same
format as for Homework 12, identify what data or metadata is
written and where it is being written.
Format of HW12 Journal Write: Transaction Begin(TxB) record,
file X data
1.
2.
3.
4.
HW11 for reference...
Let's start with a memory system that is byte addressable and has 14-bit addresses. Now let's add a direct mapped cache that can hold 16 blocks (or has 16 lines) and each block is 4 bytes. The table shoun below details the contents of the cache at a particular point in time. if the valid bit is 1 there is a cache block loaded into the cache with Tag as detailed in the tag column. The columns B0-D3 then show...
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