1
vote
1answer
69 views

Why is my synchronized I/O so bad compared to direct?

I have two 3TB disks in a software RAID 1 setup and the host OS is 64bit Debian wheezy. Issuing: dd if=/dev/zero of=test bs=64k count=3k oflag=direct && rm test Yields: 201326592 bytes ...
2
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2answers
314 views

How do I know if my disks are being hit with too many I/O reads or writes or both?

I know a bit about disk I/O and bottlenecks relating to this especially when relating to databases. How do I really know what the max I/O numbers will be for my disks? What metric might be available ...
2
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1answer
3k views

Debugging IO Limitation

I have a Fedora box with some severe IO limitations which I have no idea how to debug. The server has a Areca Technology Corp. ARC-1130 12-Port PCI-X to SATA RAID Controller with 12 7200 RPM 1.5 TB ...