About "iscsi" on monperrus.net

by Martin Monperrus
#7 Lightweight estimation of disk misalignment performance penalty (January 16, 2012)
Modern disks have a physical sector size that is larger than 512B, but the software chain (BIOS, OS, partitioning tools) generally assumes a sector size of 512B. As a result, first, I/O requests that are smaller than the physical sector size are actually translated to larger requests. >>> read more
#6 Performance of Amazon Elastic Block Store (EBS) (November 05, 2011)
I've recently started using Amazon EC2 and their "[[http://aws.amazon.com/ebs/|Elastic Block Store (EBS)]]" technology. EBS is a kind of network block storage similar to Linux's [[http://www.linuxjournal.com/article/3778|NBD]] or [[http://en.wikipedia.org/wiki/ISCSI|iSCSI]]. >>> read more
#5 Precisely measuring the maximal disk latency (July 12, 2011)
See also http://www.monperrus.net/martin/performance-of-amazon-elastic-block-store The maximal end-to-end latency of a hard-drive is achieved with accessing a random sector (it includes transfer time). The program seeker.c published at http://www.linuxinsight.com/how_fast_is_your_disk. >>> read more
#4 Scheduler queue size and resilience to heavy IO (July 11, 2011)
My server regularly stalled, freezed and sometimes crashed under heavy write accesses (open-iscsi on root filesystem). I solved the problem by changing the scheduler and increasing the maximal I/O queue size (nr_requests). >>> read more
#3 I/O Scheduling for SAN and Virtualization (July 10, 2011)
I recently encountered performance and reliability problems using iSCSI. One of the most efficient solutions was to set the I/O scheduler to "noop". Noop is the simplest elevator/scheduler in Linux. It is based on FIFO -- first request in, first out. >>> read more
#2 Heads and sectors for partition alignment (July 01, 2011)
There are many cases where [[http://www.ibm.com/developerworks/linux/library/l-4kb-sector-disks/index.html?ca=dgr-lnxw074KB-Disksdth-LX|aligning the disk partitions yields better perfomance]], for instance for database partitions, solid-state disks (SSD), and SAN storage with iSCSI. >>> read more
#1 Performance of read-write throughput with iscsi (June 14, 2011)
I recently encountered some performance issues using iSCSI. I use the open-iscsi implementation on the client side. After hours of googling and trial and errors, here are some points related to the performance of iSCSI. >>> read more