From mboxrd@z Thu Jan 1 00:00:00 1970 From: Muneendra Kumar M Subject: Re: deterministic io throughput in multipath Date: Mon, 26 Dec 2016 09:42:48 +0000 Message-ID: <8cd4cc5f20b540a1b8312ad485711152@BRMWP-EXMB12.corp.brocade.com> References: <1649d4b8538d4b4cb1efacdfe8cf31eb@BRMWP-EXMB12.corp.brocade.com> <20161221160940.GG19659@octiron.msp.redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Return-path: Content-Language: en-US List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dm-devel-bounces@redhat.com Errors-To: dm-devel-bounces@redhat.com To: Benjamin Marzinski Cc: "dm-devel@redhat.com" List-Id: dm-devel.ids Hi Ben, If there are two paths on a dm-1 say sda and sdb as below. # multipath -ll mpathd (3600110d001ee7f0102050001cc0b6751) dm-1 SANBlaze,VLUN MyLun size=3D8.0M features=3D'0' hwhandler=3D'0' wp=3Drw `-+- policy=3D'round-robin 0' prio=3D50 status=3Dactive |- 8:0:1:0 sda 8:48 active ready running `- 9:0:1:0 sdb 8:64 active ready running = And on sda if iam seeing lot of errors due to which the sda path is fluctua= ting from failed state to active state and vicevera. My requirement is something like this if sda is failed for more then 5 time= s in a hour duration ,then I want to keep the sda in failed state for few h= ours (3hrs) And the data should travel only thorugh sdb path. Will this be possible with the below parameters. Can you just let me know what values I should add for delay_watch_checks an= d delay_wait_checks. Regards, Muneendra. -----Original Message----- From: Muneendra Kumar M = Sent: Thursday, December 22, 2016 11:10 AM To: 'Benjamin Marzinski' Cc: dm-devel@redhat.com Subject: RE: [dm-devel] deterministic io throughput in multipath Hi Ben, Thanks for the reply. I will look into this parameters will do the internal testing and let you k= now the results. Regards, Muneendra. -----Original Message----- From: Benjamin Marzinski [mailto:bmarzins@redhat.com] = Sent: Wednesday, December 21, 2016 9:40 PM To: Muneendra Kumar M Cc: dm-devel@redhat.com Subject: Re: [dm-devel] deterministic io throughput in multipath Have you looked into the delay_watch_checks and delay_wait_checks configura= tion parameters? The idea behind them is to minimize the use of paths that= are intermittently failing. -Ben On Mon, Dec 19, 2016 at 11:50:36AM +0000, Muneendra Kumar M wrote: > Customers using Linux host (mostly RHEL host) using a SAN network for > block storage, complain the Linux multipath stack is not resilient to > handle non-deterministic storage network behaviors. This has caused ma= ny > customer move away to non-linux based servers. The intent of the below > patch and the prevailing issues are given below. With the below design= we > are seeing the Linux multipath stack becoming resilient to such network > issues. We hope by getting this patch accepted will help in more Linux > server adoption that use SAN network. > = > I have already sent the design details to the community in a different > mail chain and the details are available in the below link. > = > [1]https://urldefense.proofpoint.com/v2/url?u=3Dhttps-3A__www.redhat.c= om_archives_dm-2Ddevel_2016-2DDecember_msg00122.html&d=3DDgIDAw&c=3DIL_XqQW= OjubgfqINi2jTzg&r=3DE3ftc47B6BGtZ4fVaYvkuv19wKvC_Mc6nhXaA1sBIP0&m=3DvfwpVp6= e1KXtRA0ctwHYJ7cDmPsLi2C1L9pox7uexsY&s=3Dq5OI-lfefNC2CHKmyUkokgiyiPo_Uj7MRu= 52hG3MKzM&e=3D . > = > Can you please go through the design and send the comments to us. > = > =A0 > = > Regards, > = > Muneendra. > = > =A0 > = > =A0 > = > References > = > Visible links > 1. = > https://urldefense.proofpoint.com/v2/url?u=3Dhttps-3A__www.redhat.com_ar > chives_dm-2Ddevel_2016-2DDecember_msg00122.html&d=3DDgIDAw&c=3DIL_XqQWOjub > gfqINi2jTzg&r=3DE3ftc47B6BGtZ4fVaYvkuv19wKvC_Mc6nhXaA1sBIP0&m=3DvfwpVp6e1K > XtRA0ctwHYJ7cDmPsLi2C1L9pox7uexsY&s=3Dq5OI-lfefNC2CHKmyUkokgiyiPo_Uj7MRu > 52hG3MKzM&e=3D > -- > dm-devel mailing list > dm-devel@redhat.com > https://urldefense.proofpoint.com/v2/url?u=3Dhttps-3A__www.redhat.com_ma > ilman_listinfo_dm-2Ddevel&d=3DDgIDAw&c=3DIL_XqQWOjubgfqINi2jTzg&r=3DE3ftc= 47B6BGtZ4fVaYvkuv19wKvC_Mc6nhXaA1sBIP0&m=3DvfwpVp6e1KXtRA0ctwHYJ7cDmPsLi2C1= L9pox7uexsY&s=3DUyE46dXOrNTbPz_TVGtpoHl3J3h_n0uYhI4TI-PgyWg&e=3D