The term read/write head takes to find the data on the disk platter. When IO operation occurs on the disk drive, the head needs to leap to the correct data position. The actual physical positioning of the read/write head called seeking. The amount of span the head takes to move from one place to other …
Sequential means forming or following in a logical order or sequence. Random is anonym of the Sequential which means that without any logical sequence. Let’s understand the concept with the explanation. We will also answer Mr Justin’s questions in detail. Sequential IOs: Edit Image As you see the IOs are flowing from A to G …
Organisations can choose from a variety of disaster recovery methods, or combine several: Back-up: This is the simplest type of disaster recovery and entails storing data off-site or on a removable drive. However, just backing up data provides only minimal business continuity help, as the IT infrastructure itself is not backed up. Cold Site: In this type …
What is Desaster? For an organisation, anything causing disruptions to operations can be termed as a disaster. It includes a system/server crash or a natural calamity that caused an outage for a complete site. The Desaster for me is that my laptop is not powering on or not able to start the required software or …
I was working as a support engineer in one of the Hardware giant. I was supporting Servers and Operating system. During this time, I got training for legacy storage from StorageTek. It was the first time I got exposed to storage technology. During the breaks, my classmates and I use to discuss the learnings. Here …
Before we talk about Performance lets, understand more about the “Spinning Rust”. The old Hard Drives Platters were coated in Iron Oxide, which is nothing but “Rust”. Hence the device is called “Spinning Rust”. In Morden days platters are made up of complex alloy coating on glass platters. But the name is stuck to the …
The Jargons used in the performance world. Some times they are overwhelming. Hence explaining them in the simplest way. Mr Sam and Mr Ron are friends. They both are daily wage workers. They both wanted to open a bank account in ABC bank. But Back is asking $500 as a deposit. Mr Sam earns $20 …
Technical Jargons Tried to explain the Jargons used in the performance world in the simplest form possible. Kindly let us know if you face any difficulty in understanding the concepts. Throughput Bandwidth Examples: A Shopping mall Edit Image The machine from the image is to be familiar to most of us. It is a People …
What exactly is “performance”? How well a gadget, software, or service performs in terms of reaction time. When we talk about the performance of a car or bike, we look at how fast it can travel and how much it costs. Deviation The discrepancy between the expected and actual results is defined as the deviation. …
There are many causes for host unable to discover the storage over FCoE. Such as VLAN configuration on FCoE switch, improper zoning, driver issues etc. In this post, we will talk about VN2VN mode. What is VN2VN mode and how it makes a difference? VN2VN mode: Virtual N_port to VN_port connecting two FCoE adapters on …
After upgrading ESXi host to 6.5 U1, hosts may experience the PSOD. Contributing factors: Cause : Netqueue commit phase abruptly stops due to a failure of hardware activation of an Rx queue. Workaround: The workaround for this issue is to downgrade the ESXi host to 6.0 U2. As 6.0 U2 has the fix for this …
After upgrading the ESXi host to 6.5 U1, the host may experience a PSOD. This post will help in verifying the symptoms. It also helps in summarize the cause and the solution for the issue. Symptoms: In vmkernel logs we see following messages prior to PSOD: PSOD stack : Multiple CPUs getting locked: Cause: This …
Networking is a practical subject. The more practice we do, we get better at it. With great enthusiasm, I downloaded Cisco Paket Tracer for the hands-on. After initial login, during practice typed a wrong command. Guess what I need to wait till the DNS/Domain lookup got timed out. Got in this situation multiple times. Started …
When user issue ./symcfg discover from solution enabler it sends 0x3c and 0x3b commands to the Symm and VMAX. The behaviour remains same even solution enabler software is installed on the VM hosted on ESXi host. Some times we see 0x3c/0x3b commands getting failed with following messages on ESXi host: Scsi command 0x3c is Read Buffers. …
After upgrading HP-Gen8 servers with Gen9, few of us had faced an issue where the host was unable to connect to storage. Whereat the same time Gen8 hosts can connect to the same storage without any issue. Gen9 servers come with Qlogic FCoE HBAs compared to Gen8 servers which had FC HBAs. With the latest drivers …
SAN transport is not supported for backup or restore of virtual machines residing on VVol datastores. To overcome this limitation nowadays many organization prefer to use VMware hot add backup. How Hot add backup works? Backup software runs in a virtual appliance, it takes a snapshot and create a linked clone of the target virtual …
The host is losing access to the existing NFS share when the user renames the share and present a new share with the old name of an existing share. Steps to Repro: 1. Map an NFS share to host with any name, for example, “NFS-01.” 2. “NFS-01” has a shared path as “/nas/nfs-1.” 3. Rename …
Today, I had a conversation with a customer who had recently completed the setup of the Tanzu K8S supervisory cluster. Post-setup, he upgraded vCenter from 7.0 to 7.0U1 and encountered an unexpected issue. Instead of displaying the Enterprise Plus license, the Kubernetes cluster began showing a 60-day evaluation license. He sought my assistance to resolve …
