Hello Mike, I am very appreciate for your instruction. Now I can set hw_max_sectors through targcli when i create the device. I set it to 8192 same as raw rbd device. The performance improve a little, 4M seq write increase from 24MB/s to 40MB/s.(hw_max_sectors 64->8192, it is a /backstore/user:rbd/disk_xxx device) But it is far away from block device, if I usr /backstore/block 4M seq write it will be 500MB/s, performance is still a big problem.(first I should map a rbd device , then export it by targetcli)
The performance difference between /backstore/user:rbd/ and /backstore/block is so big, is it normal? Could you give me some suggestions about improving the performance of /backstore/user:rbd/ device. Thanks very much! 在 2018年9月3日星期一 UTC+8上午10:31:48，3kbo...@gmail.com写道： > > Hello Mike, > > Thank you for your informative response. > > > 在 2018年8月28日星期二 UTC+8上午8:49:46，Mike Christie写道： >> >> On 08/21/2018 08:52 PM, 3kbo...@gmail.com wrote: >> > Hi folks, >> > >> > I am newbie to open-iscsi. >> > My case is I export ceph rbd by open-iscsi. >> > >> > I found the max_sectors_kb is 64, the value is so small, and 4M >> sequence >> > write is only about 10MB/s. >> > I can not increase max_sectors_kb, if I do it will return "bash: echo: >> > write error: Invalid argument"(But I can change the value to a small >> one >> > < 64, max_hw_sectors_kb is 32767) >> > >> >> In new version of the linux kernel the initiator will use the optimal >> value reported by the target and then uses the max reported as the limit >> that the user can set. It sounds like you are using rbd/ceph with >> tcmu-runner which has a default limits of 64K. >> > Yes, I am using tcmu-runner and gwcli. > >> >> If you are using targetcli/lio directly then you can set hw_max_sectors >> through targcli when you create the device or in the saveconfig.json >> file. >> >> If you are using the ceph-iscsi tools then I am actually working on a >> gwcli command to configure this right now. >> > Yes, I am using ceph-iscsi tools.How can I change the limit by ceph-iscsi > tools? > > Thanks. > > -- You received this message because you are subscribed to the Google Groups "open-iscsi" group. To unsubscribe from this group and stop receiving emails from it, send an email to open-iscsi+unsubscr...@googlegroups.com. To post to this group, send email to firstname.lastname@example.org. Visit this group at https://groups.google.com/group/open-iscsi. For more options, visit https://groups.google.com/d/optout.