We noticed that a logical path failure will hang io on the server for about 30 seconds. From traces it looks like 20 seconds is some king of timeout waiting to be expired i suspect some kind of scsi. With openvmtools installed the scsi timeout for virtual block devices are not automatically increased anymore. When the timeout expires, the scsi mid level attempts error. If not then the scsi layer will bother us after a timeout. Dec 27, 20 from traces it looks like 20 seconds is some king of timeout waiting to be expired i suspect some kind of scsi command timeout another 7 seconds is spent with mpio to disable that logical path. Channel is the scsi bus address which will always be zero. By using linux pseudo scsi device drivers which bridge between the native protocol stack and the scsi subsystem, the upper level scsi device drivers, including sg, can be used to control non scsi devices. It focuses on the the interface and characteristics of the driver that application writers may need to know. If the timeout expires before a scsi command completes, error recovery starts. Example in the following example, the timeout of a scsi device 1.
Were using dell equallogic as sr for vm disk space. A scsi bus timeout occurs when either the scsi controller or the scsi device detects that a command has not been responded to within a. If a reenumerate is initiated in the diagnostics section, openmanage sends a scsi command to the drive that it cannot handle and results in a timeout condition leading to additional id 11 events posted in the system log by the adaptec driver. Scsi interfaces guide the linux kernel documentation. If udev is not in use, the default timeout is 30 seconds. Scsi command timeout in the san causes scsi commands to hang.
The linux scsi upper level drivers, including sg, have a trickle down ioctl architecture. I am trying to debug a situation where the ssd on my hardware is not being detected by the right device driver. When this timer expires, the scsi layer will quiesce the host bus adapter hba and wait for all outstanding commands to either time out or complete. The scsi subsystem uses a three layer design, with upper, mid, and low layers.
Scsi disks are labeled devsda, devsdb, devsdc, etc. What are linux scsi command timeouts and is the default suited for software raid. Xen, kvm, openvz, virtualbox, vmware, linux vserver and all other linux virtualization platforms are welcome. If the default increase is insufficient for a given environment or if an increase is desired and the vmware tools is not or cannot be installed, the scsi device timeout within the linux guest operating system can be increased manually. Troubleshooting scsi lun scanning issues support suse. A scsi bus timeout occurs when either the scsi controller or the scsi device detects that a command has not been responded to within a specific timeout period. Scsi timeout for linux guest last updated january 17, 2009 in categories howto, linux, linux distribution, monitoring, networking, package management, redhatfedora linux.
Is it correct to assume the default scsi timeout is meant for desktop purposes or nonhdd scsi equipment tape drive, tape library come to. Nov 09, 2015 linux software raid and drive timeouts. Vmware tools creates a udev rule to change the timeout for devices classified by vendor vmware or attribute virtual disk from 30 seconds to 180 seconds. There is a mailing list for bug reports and questions regarding scsi development under linux.
The argument is an integer representing the timeout in seconds. Consult the dell emc storage compatibility matrix for the most uptodate recommended values. By joining our community you will have the ability to post topics, receive our newsletter, use the advanced search, subscribe to threads and access many other special features. This rule does not apply to raw devices since they do not appear as virtual disks to the vm. If theres nothing above in the log, its impossible to say which command timed out. Where are the scsi timeouts set for the block devices xvd in linux guests. Getting scsi timeout errors on redhat linux guest oses.
This driver version is part of the linux kernels from version 2. When eql failover happens, vmcentos always remounts its file system as ro mode and we need to reboot them for recovering. You can specify either a 60second timeout or a 190second timeout. Determine linux driver that owns a disk stack overflow. Linux software raid and drive timeouts the ongoing struggle. Next, he explains the linux generic scsi driver api and offers an example of using a system that focuses. That timeout is set high for desktop drives typically standalone, so correction has high priority and low for server drives typically raid, so report bad sector soon, let other drive answer. The device driver that should own the ssds is a software raid driver megasr that will. It includes generic scsi target core with scsi target drivers and backend handlers.
Query the timeout period of a scsi device oceanstor ultrapath. The default timeout for the linux kernels before 2. The driver returns the real timeout used in the same variable, and this timeout might differ from the requested one due to limitation of the hardware. Every operation involving the scsi subsystem such as reading a sector from a disk uses one driver at each of the 3 levels. If there is another solution im all ears but from my research it looks like its a driver issue and increasing the timeout resolves it. Applications that run on top of the file system typically send io requests to files while databases fire them directly on raw devices. Contribute to torvaldslinux development by creating an account on github.
Can the hard drive timeout be disabled in linux attempting task abort. Automatic startup of infiniband drivers querying infiniband driver configurations. Openstack, cloudstack, owncloud, cloud foundry, eucalyptus, nimbus, opennebula and all other linux. Howto configure the linux kernel drivers scsi in general it is a good idea to enable scsi device support even if you dont use scsi disks often cameras, usb drives, mp3 mplayers, etc. On linux, you can get the io timeout value from each block device by reading the value on. How to configure the linux kerneldevice driversscsi device. A hard disk encountering a read error will try hard to correct the error within a time frame defined by firmware. Are there recommended scsi timeout values for using raw devices on linux vms. Once device initialization is complete, the linux scsi disk driver interfaces sd send only scsi.
This series has a huge amount of churn because it pulls in mauros doc update changing all our txt files to rst ones. This article attempts to outline how veritas dmp handle io failures on linux redhat. Have i correctly diagnosed this as an expected response to a scsi command timeout. With the disadvantage that you maybe cant log in to them and change their timeout. Linux virtualization and cloud this forum is for the discussion of all topics relating to linux virtualization and linux cloud platforms. Debian detects io error, but keeps its file system wit. Architecture the scsi generic packet device driver sg is a character based device. He provides background on the scsi clientserver model and the storage scsi command. To keep scanning times to a minimum, it is strongly recommended to use a large buffer size for the generic scsi driver. Controlling the scsi command timer and device status red. To find out the current timeout, read the timeout attribute of the scsi device.
The port enable still times out with the port enable. Resolution manually create an extra udev rule that increases the scsi timeout for all virtual block devices if this behaviour is still desired. What are linux scsi command timeouts and is the default suited for. I currently have a disk that refuses to spinup, unless you tell it to do so repeatedly.
The combination of the timeout parameters must be such that scsi commands are finished in a reasonable time. Ioaccel is an alternative driver submission path that allows the driver to send io requests directly to backend scsi devices, bypassing the controller firmware. Setting persistent scsi timeout red hat customer portal. This frees the lowlevel driver from having to do timing, and permits different timeout periods to be used for different devices e. It is one of the four high level device driver in the scsi subsystem. Scsi command timeout in the san causes scsi commands to hang in fcp driver doc id 2350556. The third number correlates to the storage center front end ports targets. When a disk becomes faulty means when the system encouters a medium error, etc i want the linux scsi subsystem to be more robust much like that of sunos 4 or sunos 5 scsi subsytems.
The luns and targets information can also be found in proc scsi scsi. These are notes on the linux scsi generic packet device driver sg describing version 2. Dec 16, 2011 hi, i have a problem to change the configuration of disk timeout. Scsi timeouts would be a driver specific item in a linux box. How to configure the linux kerneldevice driversscsi. When the timeout expires, the scsi mid level attempts error recovery. How do the timeouts work up the chain if the underlying pbd is an iscsi lun. Red hat enterprise linux 7 subscriber exclusive content a red hat subscription provides unlimited access to our knowledgebase of over 48,000 articles and solutions. The st driver provides the interface to a variety of scsi tape devices. Scsi devices under linux are often named to help the user identify the device. The last number is the lun that the volume is mapped on.
The linux vm has 1 hard drive devsda only, which should look like a regular scsi type of physical drive to it. Increasing the scsi timeout value is to alleviate the issue of slow failovertransient storage conditions. Attachment requirements for hosts that are running the. Solaris operating system version 10 1 u11 and later. Running the gos timeout scripts for linux the guest operating system timeout scripts set the scsi io timeout settings for rhel4, rhel5, rhel6, sles9, sles10, and sles11.
The thing about these is, theyre quite often just lowend hardware running linux and doing linux software raid under the covers. The hba portdown timeout parameter dictates how long a linux system waits before destroying a connection after losing its connectivity with the port. Vmware tools creates a udev rule to change the timeout. Hi, i am doing some testing for windows 2008 r2 sp1 boot from san with qlogic hbas. If the timeout period of the scsi device is different from that in the udev file of. The type of timeout is unsigned int and it represents milliseconds. Are scsi command timeouts acceptable, or are they to be avoided by increasing the timeout time. This produces up to five 5 id 11 events in the system log. Under certain circumstances this detection might fail or not be completely correct. The rhel 5 manual describes the way to set scsi disk timeouts in a persistent way. In this article, the author introduces some of the scsi commands and methods of executing scsi commands when using scsi api in linux. Of maximum importance to me is keeping the drives online. With these scsi unit attentions, it is possible to have the linux initiator autorescan on. Automatically setting scsi timeout with openvmtools installed.
Afterwards, the scsi layer will activate the drivers error handler. Im simply asking how to increase the scsi io timeout in esxi. The default scsi timeout value is 90 seconds for kernel 3. Scsi device support, scsi devproc support, and scsi disk support option. Controlling the scsi command timer and device status.
Normally, commands are issued by the scsi controller, which then waits for a response from the device being addressed. Ill be updating sourceforge with the driver later today. Scsi scanning flags sles8 only sles8 uses an older. If a disk has some problems, the disk driver usually retries it. It is not designed to mitigate prolonged underlying. This manual page contains various operatingsystem specific tips and tricks on how to get scanners with a scsi interface working. Generic scsi target subsystem for linux scst allows creation of sophisticated storage devices. I tried searching the internet for such a timeout on windows and could not find any. Amd scsi chip host adaptor with tmscsim driver thanks to kurt garloff. Setting the scsi command timeout for linux on ibm z z.
Windows servers have the disk timeout set to 120 seconds in the registry, and then under that is the standard xen iscsi target timeout. Unable to abort command to target 0 ccb resetto unsubscribe from this list. It then sets the driver byte to show what it has done. The general flow of io through a multipathed stack can be summarized in the diagram below. Possible values for scsi driver status byte byte 3 are. The portdown timeout is generally set to 60 seconds for the sc series storage system. Device\scsi\adpu160m2, did not respond within the timeout. When a disk becomes faulty means when the system encouters a medium error, etc i want the linux scsi subsystem to be more robust much like that of sunos 4 or sunos 5 scsi. For example, sometimes linux scsi driver will get busy status from scsi drives and resend the io.
This howto describes the scsi generic driver sg found in the linux 2. Hi, i wanted to change the scsi disk spinuptime timeout. What are linux scsi command timeouts and is the default. The internet small computer system interface iscsi is an ipbased standard for connecting storage devices. Scsi timout value rdms in linux vms vmware communities. Currently, the driver takes control of all detected devices of type sequentialaccess.
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