When the economy meets the performance the iScsi comes into play!
\nI am using 1Gb ethernet between the target and the initiator (both on CentOs 6.3).
\nThe target consists of the 3ware controller with 4 SSD Ocz Vertex 3. So, the backing-store is the device \/dev\/sda\/ (\/etc\/tgt\/targets.conf).
\nNext, Parted and LVM configured on the target with xfs.<\/p>\n
parted \/dev\/sde\r\nmklabel gpt\r\nmkpart \r\n\r\n[name] primary\r\n[fs] xfs\r\n[start] 0%\r\n[stop] 100%\r\n\r\nset 1 lvm on<\/pre>\npvcreate \/dev\/sde1\r\nvgcreate vg_s7v0_ssd \/dev\/sde1\r\nlvcreate -C y -n data -l 98%FREE vg_s7v0_ssd # rest for snapshot\r\nmkfs.xfs -f -d su=256k,sw=3 \/dev\/vg_s7v0_ssd\/data\r\nsu = < RAID controllers stripe size in BYTES (or KiBytes when used with k) >\r\nsw = <# of data disks (don't count parity disks)>\r\n\r\nxfx_info \/dev\/vg_s7v0_ssd\/data<\/pre>\nThe problem I encountered was that after target reboot it used isci device (configured on target) locally. So it was impossible to connect it to the initiator… The solution was to set the filters on the target. However, it did NOT work when the rule “a\/.*\/” was in the config. This is my case (only one “variable” filter is used):<\/p>\n
# By default we accept every block device:\r\nfilter = [ \"r|\/dev\/sda1|\", \"r|\/dev\/sda|\", \"a|\/dev\/sdd|\", \"a|\/dev\/sdc|\" ]<\/pre>\nYou have to ensure that the initiator connect to the target on startup, you do it with the following command<\/p>\n
iscsiadm -m node --target iqn.2012.local.fs07:ssd.lun0 -p 10.0.0.1 --op update -n node.startup -v automatic<\/pre>\nAdd to the grub.conf elevator=noop (io scheduling mode) and mount with the options noatime,nodiratime,nobarrier.
\nIf you use iscsi – add “_netdev” (device requires network to be available) – thank God! \ud83d\ude42<\/p>\n
UUID=\"79a594d6-de0b-477c-bad5-8f4bc77267be\" \/db_storage_ssd xfs noatime,nodiratime,nobarrier,_netdev 0 0<\/pre>\nFinally, I obtained the following numbers on SSD RAID 10 (measured with sysbench)<\/p>\n
200Mb total file size\r\nBlock size 16Kb\r\nNumber of random requests for random IO: 10000\r\nRead\/Write ratio for combined random IO test: 1.50\r\nCalling fsync() at the end of test, Enabled.\r\nOperations performed: 0 Read, 10000 Write, 1 Other = 10001 Total\r\nRead 0b Written 156.25Mb Total transferred 156.25Mb (80.4Mb\/sec)\r\n 5145.57 Requests\/sec executed\r\n\r\nOperations performed: 10000 Read, 0 Write, 0 Other = 10000 Total\r\nRead 156.25Mb Written 0b Total transferred 156.25Mb (110.72Mb\/sec)\r\n 7085.88 Requests\/sec executed<\/pre>\nCommon administration tasks on target:
\nDynamic initiator management:<\/p>\n
\r\n# add ACL\r\ntgtadm --lld iscsi --mode target --op bind --tid 4 --initiator-address 10.0.15.206\r\n# del ACL\r\ntgtadm --lld iscsi --mode target --op unbind --tid 4 --initiator-address 10.0.15.206\r\n\r\ninsert new initiator and then start it (w\/o restarting services)\r\n\r\n\t# Update configuration for targets. Only targets which\r\n # are not in use will be updated.\r\n\/etc\/init.d\/tgtd reload \r\n<\/pre>\nCommon administration tasks on initiator:
\nDisconnect initiator on lvm (clean)<\/p>\n
\r\numount \/db_storage_ssd1\r\numount \/db_storage_ssd2\r\nvgchange -ay vg_mysql_ssd1 && vgchange -ay vg_mysql_ssd2\r\niscsiadm -d 1 --mode node -p 10.0.15.233 --logout all\r\n# or separately\r\niscsiadm -d 1 --mode node --target iqn.2012.local.fs05:ssd.lun0 -p 10.0.15.233 --logout\r\n\r\n# active sessions\r\niscsiadm -m session\r\n# detailed\r\niscsiadm -m session -P1\r\n\r\nYou can find very interesting information in one of Oracle'a White Paper about\r\nsun Flash Accelerator f80 PCIe Card<\/a><\/pre>\n (another elevator and with another fs – ext4).<\/p>\n","protected":false},"excerpt":{"rendered":"
When the economy meets the performance the iScsi comes into play! I am using 1Gb ethernet between the target and the initiator (both on CentOs 6.3). The target consists of the 3ware controller with 4 SSD Ocz Vertex 3. So, the backing-store is the device \/dev\/sda\/ (\/etc\/tgt\/targets.conf). Next, Parted and LVM configured on the target […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[7,18],"tags":[],"_links":{"self":[{"href":"http:\/\/10sa.com\/sql_stories\/index.php?rest_route=\/wp\/v2\/posts\/563"}],"collection":[{"href":"http:\/\/10sa.com\/sql_stories\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/10sa.com\/sql_stories\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/10sa.com\/sql_stories\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/10sa.com\/sql_stories\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=563"}],"version-history":[{"count":34,"href":"http:\/\/10sa.com\/sql_stories\/index.php?rest_route=\/wp\/v2\/posts\/563\/revisions"}],"predecessor-version":[{"id":888,"href":"http:\/\/10sa.com\/sql_stories\/index.php?rest_route=\/wp\/v2\/posts\/563\/revisions\/888"}],"wp:attachment":[{"href":"http:\/\/10sa.com\/sql_stories\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=563"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/10sa.com\/sql_stories\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=563"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/10sa.com\/sql_stories\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=563"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}