diff --git a/scst/README b/scst/README index 1412d3df4..d51773400 100644 --- a/scst/README +++ b/scst/README @@ -1935,11 +1935,8 @@ intensive writes from VMware on a target disk, which uses LVM in the snapshot mode. In this case value like 16 or even 8-10 depending of your backstorage speed could be more appropriate. -Unfortunately, currently SCST lacks dynamic I/O flow control, when the -queue depth on the target is dynamically decreased/increased based on -how slow/fast the backstorage speed comparing to the target link. So, -there are 6 possible actions, which you can do to workaround or fix this -issue in this case: +There are 6 possible actions, which you can do to workaround or fix such +issues: 1. Ignore incoming task management (TM) commands. It's fine if there are not too many of them, so average performance isn't hurt and the @@ -1976,10 +1973,11 @@ By default, this timeout is 30 or 60 seconds, depending on your distribution. 5. Increase speed of the target's backstorage. -6. Implement in SCST dynamic I/O flow control. This will be an ultimate -solution. See "Dynamic I/O flow control" section on -http://scst.sourceforge.net/contributing.html page for possible -implementation idea. +6. Implement in SCST dynamic I/O flow control, so queue depth on the +target is dynamically decreased/increased based on how slow/fast the +backstorage speed comparing to the target link. See "Dynamic I/O flow +control" section on http://scst.sourceforge.net/contributing.html page +for possible implementation idea. Next, consider the case of too slow link between initiator and target, when the initiator tries to simultaneously push N commands to the target diff --git a/scst/README_in-tree b/scst/README_in-tree index a262c531d..1e73cfb8d 100644 --- a/scst/README_in-tree +++ b/scst/README_in-tree @@ -1440,11 +1440,8 @@ intensive writes from VMware on a target disk, which uses LVM in the snapshot mode. In this case value like 16 or even 8-10 depending of your backstorage speed could be more appropriate. -Unfortunately, currently SCST lacks dynamic I/O flow control, when the -queue depth on the target is dynamically decreased/increased based on -how slow/fast the backstorage speed comparing to the target link. So, -there are 6 possible actions, which you can do to workaround or fix this -issue in this case: +There are 6 possible actions, which you can do to workaround or fix such +issues: 1. Ignore incoming task management (TM) commands. It's fine if there are not too many of them, so average performance isn't hurt and the @@ -1481,10 +1478,11 @@ By default, this timeout is 30 or 60 seconds, depending on your distribution. 5. Increase speed of the target's backstorage. -6. Implement in SCST dynamic I/O flow control. This will be an ultimate -solution. See "Dynamic I/O flow control" section on -http://scst.sourceforge.net/contributing.html page for possible -implementation idea. +6. Implement in SCST dynamic I/O flow control, so queue depth on the +target is dynamically decreased/increased based on how slow/fast the +backstorage speed comparing to the target link. See "Dynamic I/O flow +control" section on http://scst.sourceforge.net/contributing.html page +for possible implementation idea. Next, consider the case of too slow link between initiator and target, when the initiator tries to simultaneously push N commands to the target