We ran tests with the SmartConnect configuration in place and the SMB shares were mounted using the SmartConnect zone name.
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We ran tests with the SmartConnect configuration in place and the SMB shares were mounted using the SmartConnect zone name.
As video is being written to the storage, video is simultaneously recalled or reviewed at a rate equal to 20 percent of the write rate. The review did not affect the write rate, video quality, or result in dropped video.
A single disk failure is the most common failure affecting storage systems today. When a disk fails, that disk is removed and replaced. The replacement disk is then reconstructed.
The Isilon cluster was protected using a +2 protection scheme that allows for two simultaneous disk failures. For the test, two disks are failed and then recovered. The SmartFail process started and the CPU utilization of the node increased with no observed effect to the write streams.
The Isilon hard NIC failure test removes one NIC cable from the active node that was involved in active recording. After the NIC failure, writing to the same node failed. When the network fails, the server must recognize the failure, then it must establish a new connection. Also, when the network fails TCP socket connections are left open and remain open on the cluster until Isilon's OneFS forces them closed, which allows the server to continue writing.
We can force the open TCP sockets to close for a duration of less than 2 minutes by reducing the TCP keep idle and TCP keep interval timeout to the optimum values recommended by Isilon Engineering.
To reduce the video loss duration due to the TCP Socket Open condition, set the persistent values in the sysctl.config file as follows to reduce the impact duration time significantly:
isi_sysctl_cluster
net.inet.tcp.keepidle=61000
isi_sysctl_cluster
net.inet.tcp.keepintvl=5000
Refer to the KB Article 89232, Configuring sysctls and making sysctl changes persist through node and cluster reboots and upgrades for further information about how to configure these parameters.
The hard NIC failure test with Active/Passive aggregation was run by removing the active NIC port cable. After the network failure, writing to the same node continued and the NIC that was passive was immediately changed to the active NIC. The NIC failure caused no apparent loss.
TCP transmission timers can be adjusted to reduce the reconnection times during Nic failures on recorders that use Microsoft MPIO. For more information, see the .
An unexpected single node hard failure was simulated, which causes the servers that were writing to that node to reconnect to a new node.
During the tests, the servers on the failed node reconnected to a new node, but did not start writing again for an aggregate (reconnect and start writing) duration of up to 52 seconds while waiting for writing to the SMB share to be re-started.
Also, the removal or addition of a node causes an interrupt to the cluster. Therefore, video servers writing to the other nodes might experience a short interruption. The duration of the interruption can be reduced by modifying the OneFS environment variables.
The following changes are required to modify the remove or add node interruption:
declare -i COUNT MDS
BASE=10000
COUNT=$((1.01 * $BASE))
MDS=$(($BASE * 0.75))
isi_sysctl_cluster kern.maxvnodes=$BASE
isi_sysctl_cluster kern.minvnodes=$BASE
isi_sysctl_cluster efs.lin.lock.initiator.lazy_queue_goal=$COUNT
isi_sysctl_cluster efs.ref.initiator.lazy_queue_goal=$COUNT
isi_sysctl_cluster efs.mds.block_lock.initiator.lazy_queue_goal=$MDS
isi_sysctl_cluster efs.bam.datalock.initiator.lazy_queue_goal=$MDS
If running a mixed workload, these changes can adversely affect the other workloads that might be present on the cluster.