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The -b option in tar was used to control the block size tar writes to a device, so that is exactly what you want. But -b 512 regarding the manual page tar(1) means a block size of 512*512 = 262144. All block sizes are valid that your device, you write the tar output to, can handle. In history this was needed for different tape drives the tar command was ...


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There is a package called buffer in Debian that is probably the program you're remembering. It was last updated upstream in 2001 and the URL recorded as the source is no longer live. If your distribution doesn't provide it, you can get the source or a binary package from Debian. The buffer program sets up a buffer between a producer and a consumer which may ...


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My answer has 2 parts: investigation of the block device driver; an optimisation worth looking at with your use case. Investigation of Hardware I understood that for the same application but on 2 different hardware the performance is very different and you would like to understand why. Therefore I propose first a mean to help you find an answer for the ...


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jbd2 process is for ext4 journalling. It is logical that filesystem needs to write into journal during mysql commits, this should not be reason for any worries. The amount of load caused by jbd is influenced by your mount parameters for dm-10-8 and dm-14-8 partitions. It is probably desirable to have very conservatiove journalling at database partition to ...


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Your system is swapping heavily (17G swap used) which will make any I/O from regular processes to the respective drive extremely slow - which translates into high %wa. Not 100% sure but even swapping itself may contribute directly to the %wa figure as well (typically via the kswapd process, also likely the top CPU hugger in your situation). First you want ...


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sudo iotop gives you a nice, top-like overview of all disk io activty like this: To install, use sudo apt-get install iotop


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$ pidstat -d 5 Should print processes and their disk activity every 5 seconds. Pidstat can be found in the sysstat package. $ sudo apt-get install sysstat



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