From: Tang Junhui <tang.junhui@xxxxxxxxxx> There is a machine with very little max_sectors_kb size: [root@ceph151 queue]# pwd /sys/block/sdd/queue [root@ceph151 queue]# cat max_hw_sectors_kb 256 [root@ceph151 queue]# cat max_sectors_kb 256 The performance is very low when I run big I/Os. I can not modify it directly, I need a little bigger, so how can I enlarge it? the system info: [root@ceph151 queue]# uname -r 3.10.0-327.22.2.el7.x86_64 [root@ceph151 queue]# lsmod |grep scsi scsi_transport_fc 64056 1 lpfc scsi_tgt 20027 1 scsi_transport_fc [root@ceph151 queue]# lsscsi [0:0:0:0] disk ASR7805 system V1.0 /dev/sda [0:1:8:0] disk ATA Hitachi HUA72201 JP4O /dev/sdb [0:1:9:0] disk ATA Hitachi HUA72201 JP4O /dev/sdc [0:1:10:0] disk ATA Hitachi HUA72201 JP4O /dev/sdd [0:1:11:0] disk ATA Hitachi HUA72201 JP4O /dev/sde [0:1:12:0] disk ATA Hitachi HUA72201 JP4O /dev/sdf [0:1:13:0] disk ATA Hitachi HUA72201 JP4O /dev/sdg [0:1:14:0] disk ATA Hitachi HUA72201 JP4O /dev/sdh [0:1:15:0] disk ATA Hitachi HUA72201 JP4O /dev/sdi [0:1:16:0] disk ATA Hitachi HUA72201 JP4O /dev/sdj [0:1:17:0] disk ATA Hitachi HUA72201 JP4O /dev/sdk [0:1:18:0] disk ATA Hitachi HUA72201 JP4O /dev/sdl [0:1:19:0] disk ATA Hitachi HUA72201 JP4O /dev/sdm [0:1:20:0] disk TOSHIBA AL13SEB600 0101 - [0:1:21:0] disk TOSHIBA AL13SEB600 0101 - [0:3:0:0] enclosu ZTE CORP 720381 EvBd 255 1 - Any comment would be wellcome. Thanks, Tang Junhui
