If the server lacks the resources to process a scsi command, linux queues the command for a later retry and decreases the queue depth counter. This limits all maximum device queue depths and disk schedule number requests outstanding to 32. Ill be testing the firmware flash another day, itll be done in another post, but today id like to quickly show howto check queue depth of storage adapter or storage device. The maximum queue depth should be chosen carefully. Hi, we have 2 hp bl460 g6 blades running sles11 sp3 and commvault simpana 10 sp8 media agent. Setting the queue depth to 0 indicates that the driver should use the system default. The default queue depth of the nfnic driver is set to 32 and on all initial releases of the nfnic driver there is no way to adjust the nfnic queue depth.
A setting of 30 seconds is recommended for linux use. How to change qdepth for red hat linuxunix support. I know emc sans like to change this number frequently. The queue depth indicates the number of io requests that are in flight, that have been requested but not yet been acknowledged to have been completed when communicating with a san storage. Benchmarking your application on azure disk storage. Hba queue depth is set to maximum allowed 8192 device lun queue depth is set to maximum allowed 512 storage port have their queue set to maximum 1600 activeactive array. Changing the queue depth for qlogic, emulex, and brocade hbas. The linux scsi code automatically adjusts the queue depth as necessary. However, since your vhbas also have vnx, you need to go with lowest value which would be of vnx. Ssds and linux native command queuing the ongoing struggle.
To adjust the maximum queue depth parameter, use the vcli commands. Howto flash dell perc h310 with it firmware to change queue depth from 25 to 600. The maximum queue depth setting can significantly influence the storage performance. The maximum value refers to the queue depths reported for various paths to the lun. Now i have the problem that the commvault simpana dedup process gets stuck regularly every few days. According to the qlogic support, the maximum scsi queue depth is set at 32 per lun by the windows environment. Reach out to your storage vendor and ask them what their best practices are on the queue depth or what they would suggest it be set to.
They are connected to a 3par storage through a qlogic 4gbits hba. When you lower this value, it throttles the hosts throughput and alleviates san contention concerns if multiple hosts are overutilizing the storage and are filling its command queue. Changing the queue depth is usually a storage server requirement. How do i set multiple different lun queue depths for. How do i set multiple different lun queue depths for different luns on. The queue depth setting specifies the number of outstanding requests per lun. The target port can accept 2048 outstanding ios in its queue before shutting down communications, the esx host in the example has 15 luns presented over that storage controller. Setting the queue depth for a scsi device on linux on ibm. Configuring the queue depth of the nfnic driver on esxi 6. I have the underlying lun adapter queue depth configured, but id like to configure a max depth of the high level striped lv. How to find the highest safe value for better hdd io. Ethernet fcoe drivers for vmware esxi, linux, and windows for the following functions.
If no indications of resource problems occur within this period, linux increases the queue. Trying to write a shell script to check the queue depth on mq server and once its reaches a particular level 5000, mail should be triggered to our mailbox saying for this queue queue depth reached to this value. Number of io which can be generated per lun with single queue depth slot ms average latency between host and storage array if latency is 10ms, server can generate 100 iops. First i needed to determine which driver module my hba is using. Does the three set lemma imply the axiom of choice. Guestinfo virtualdiskmapping linux, powercli support. Then control my actual dqlen via changing dsnro, which i can change on the fly.
How to increase the maximum queue depth per logical unit. So, when you import the disc on another system, this configuration is lost. You can use the qlogic hba management gui or commandline interface cli to modify the qlogic hba queue depth. Hi, anybody know where to set the queue depth value in linux. For queue depth there are two settings that can be adjusted. How can i dynamically change the lun queue depth of a disk. Oracle iops and hba queue depth ardent performance computing. Queue depth the maximum depth of the queue in sata is 31 for practical purposes, and so if the drive supports ncq then linux will usually set the depth to 31. Hi paul, i changed the text, i forgot to add the queue depth to that sentence. So i can set my device queue depth to the maximum and reboot once. Is there a way to set max io queue depthio queued for an lv in rhel 6.
Im trying to figure how to viewmonitorreport the queue depth on these hbas canshould i increase the hba queue depth. Writing 1 to the file effectively disables ncq for that device. Lun queue depth, and hba queue depth io throttle count. Updating qlogic hba queue depths on a linux host you can update the device queue depth of a qlogic driver on a linux host.
Specifically trying to limit the queue depth as measured through iostat. For emulex, xtremio best practice recommendation is to set hba queue depth to 8192default, and lun queue depth to 128. Typically we set 256default for qlogic, 4gbps cards. I am looking for a input parameter corresponding to queue depth but am unable to locate so. With set lun queue depth to maximum its depended to your hba, you should read hba vendor document 100 x 512 maximum lun queue depth 51,200. Queue depth is for emulex cards and execution throttle is for qlogic cards. Setting queue depth and execution throttle for qlogic. Emc host connectivity guide for linux dell technologies. I want to run an experiment where i vary this parameter and measure the io performance. If step 1 does not make the new queue depth settings stick, then we have to do a little more. It all depends on what the service process on the storage device can handle. It basically depends on the queued commands on the luns.
After cache disk is warmed up, proceed with the test scenarios listed below. In this video, rob mcnelly demonstrates how to increase the queue depth on your aix disks. Howto check queue depth of storage adapter or storage device. But if you must, heres one i used back in the early 2000s that i called chkqdepth.
Please check the lun queue depth settings on the citrix server these need to be set to 32 divided by the number of active host paths to the luns all hos. To make the updates persistent across reboots, you must then create a new ram disk image and reboot the host. Powertools changes the queue depth of the iscsi daemon to 128. A physical server perspective assuming average 10 ms latency between the host and storage array. What is the fiber channel hba queue depth, how to check the current queue depth value. For each worker thread, select the target volume, set queue depth and select one of the saved test specifications, as shown in the table below, to run the corresponding test scenario. 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.
To start out, id like to compare the default queue size of 32 with an increased setting of 64. You can change the queue depth of emulex hbas and qlogic hbas on linux hosts. How many signals can be queued on a process that has all signals blocked. Each time this happens i see a lot of these qla2xxx. How to change qdepth for red hat the default max queue depth setting is 32 for red hat. The ql2xmaxqdepth parameter defines the maximum queue depth reported to scsi midlevel per device. Is it possible to dynamically set a value higher than what is currently set in the kernel at boot from. Setting the depth of a traffic class queue controls when the router drops packets for example, using tail drop. If no indications of resource problems occur within this period, linux increases the queue depth counter until reaching the previously set maximum value. Linux forwards scsi commands to the storage server until the number of pending commands exceeds the queue depth. Fcoe driver tuning for vmware esxi, linux, and windows marvell. Understanding vmware esxi queuing and the flasharray. With qlogic hbas on linux the queue depth is configured through the ql2xmaxqdepth module option. Update the queue depths by adding the queue depth parameters to the etcnf file for a red hat enterprise linux 5.
To set the size of a class queue that is, to configure the maximum number of packets that a class queue can hold, complete the following steps. Well, i think it would be better to write an mqpcf in java or c rather than do it by a shell script. Adjust queue depth for qlogic, emulex, and brocade hbas. The maximum queue depth describes the value of requests which is allowed to be in flight at maximum. If that is increasing then it will make sense to reduce the execution throttle. One of the more confusing storagerelated settings in vmware is the schednumreqoutstanding setting. Reboot the host and confirm that the queue depth values are set correctly. Queues, queues and more queues virtualize applications. For sata disks, this is the native command queuing ncq queue depth. Is there a way to set max io queue depthio queued for an. What is the hba queue depth, how to check the current queue depth. Per microsoft driver development kit ddk, microsoft storport.
I have a windows 2003 serverx64 that is having apparent io problems to its eva storage. How to fake the amount of installed ram for a specific program in linux. Setting queue depths on linux hosts netapp documentation. What is hba queue depth and how to check the current queue. The queue depth can setting for each disk using the command scsictl m i have tested and verified that these settings are stored in the operating system kernel. To run the iometer test, use at least three worker threads for each target volume. On windows hosts, you can use the lputilnt utility to update the queue depth for emulex hbas and the sansurfer hba manager utility to update the queue. If it does not allow you to set values higher than 1, maybe your kernel has ncq disabled in general. For suse and red hat the max queue depth parameter for linux is set in nf. Setting the queue depth for a scsi device on linux on z. In the host configuration guide, on page 59, it talks about setting the lun queue depth on the emulex hba to 128. You can change it to configure etcnf rhel 5 and also add new config file to. These requests can be configured per single logical unit number lun that is accessed or based on the hba. Mitigating the effects of storage array migration for linux hosts 36.