Archive for September, 2015
Terminology: fio = https://github.com/axboe/fio/ us = microsecond = (1 / 1 000 000) second stdev = standard deviation Quick explanation: 1. Latency: 2. IOps Detailed information are available in FIO’s How-To (ยง 6.0 Interpreting the output) Example of my configuration (random writes): [global] bs=4k ioengine=libaio iodepth=4 # was 1g size=1g direct=1 runtime=60 # directory=/bcache directory=/emcpower […]
I encountered the problem that after I chose backend device as /dev/emcpowera3 I have seen 16+1 bcache-devices (bcache0-bcache16). It reflected from the fact that bcache saw all links (reading the bcache signatures). The solution apears to be very simple: vi /usr/lib/udev/rules.d/69-bcache.rules was: KERNEL==”fd*|sr*”, GOTO=”bcache_end” should be: KERNEL==”fd*|sr*|sd*”, GOTO=”bcache_end” How it looked before I changed udev […]
Bcache is not enabled by default in CentOS 7.1. However, you do not need to recompile whole kernel. It is sufficient to compile module and add it to existing kernel. yum groupinstall “Development Tools” -y yum install kernel-headers -y Unfortunately, kernel headers do not include all you need. You have to download adequate kernel sources […]
# Annoying… mdadm –create /dev/md3 –level=1 –raid-disks=2 /dev/nvme0n1p3 /dev/nvme1n1p3 [root@db7 ~]# parted /dev/nvme0n1 p Model: Unknown (unknown) Disk /dev/nvme0n1: 400GB Sector size (logical/physical): 512B/512B Partition Table: gpt Disk Flags: Number Start End Size File system Name Flags 1 1049kB 40.0GB 40.0GB primary raid 2 40.0GB 80.0GB 40.0GB mysql raid 3 80.0GB 84.0GB 4000MB xd raid […]
docker run -it -v /host_storage/mms_condor:/storage_inside_docker \ –name=”condor_swap_30″ –memory-swappiness=”30″ \ –oom-kill-disable=true -c=1024 -m 64M 7322fbe74aa5 –oom-kill-disable=true|false: Whether to disable OOM Killer for the container or not. –memory-swappiness=””: Tune a container’s memory swappiness behavior. Accepts an integer between 0 and 100. –memory-swap=””: Total memory limit (memory + swap, format: , where unit = b, k, m or […]
lvcreate -n pool0 -L 20G dockers lvcreate -n pool0meta -L 1G dockers lvconvert –type thin-pool –poolmetadata dockers/pool0meta dockers/pool0 # check how it is working? [root@db7 ~]# docker daemon –storage-opt dm.thinpooldev=/dev/mapper/dockers-pool0 Install to systemctl echo ‘OPTIONS=”–storage-opt dm.thinpooldev=/dev/mapper/dockers-pool0″‘ >> /etc/sysconfig/docker vi /usr/lib/systemd/system/docker.service [Unit] Description=Docker Application Container Engine Documentation=https://docs.docker.com After=network.target docker.socket Requires=docker.socket [Service] EnvironmentFile=-/etc/sysconfig/docker Type=notify ExecStart=/usr/bin/docker daemon -H […]