Tcpdump is a powerful command-line packet analyzer tool used in Unix and Linux operating systems. It allows users to capture and display network packets flowing through a network interface in real-time or saved to a file for later analysis. This tutorial covers the basic tcpdump filters like source ip, host, interface, specific port, udp port, …
The hardware vendor info or serial number can be very helpful to open a support case for Linux admins. We will cover this topic today to get this info from Linux system. We will use dmidecode command to get this info. The following examples show us three different platforms, physical servers, VMware VM and Openstack …
悯农二首·其二 李绅 〔唐代〕 锄禾日当午，汗滴禾下土。 谁知盘中餐，粒粒皆辛苦？ 悯农译文及注释 译文 盛夏中午，烈日炎炎，农民还在劳作，汗珠滴入泥土。 有谁想到，我们碗中的米饭，一粒一粒都是农民辛苦劳动得来的呀？ 注释 禾：谷类植物的统称。 餐：一作“飧”。熟食的通称。 悯农创作背景 根据唐代范摅《云溪友议》和《旧唐书·吕渭传》等书的记载，大致可推定这组诗为李绅于唐德宗贞元十五年（公元799年）所作。 悯农赏析 首诗描绘了在烈日当空的正午农民田里劳作的景象，概括地表现了农民终年辛勤劳动的生活，最后以“谁知盘中餐，粒粒皆辛苦”这样近似蕴意深远的格言，表达了诗人对农民真挚的同情之心。 一开头就描绘在烈日当空的正午，农民依然在田里劳作，那一滴滴的汗珠，洒在灼热的土地上。这就补叙出由“一粒粟”到“万颗子”，到“四海无闲田”，乃是千千万万个农民用血汗浇灌起来的；这也为下面“粒粒皆辛苦”撷取了最富有典型意义的形象，可谓一以当十。它概括地表现了农民不避严寒酷暑、雨雪风霜，终年辛勤劳动的生活。 “谁知盘中餐，粒粒皆辛苦”，不是空洞的说教，不是无病的呻吟；它近似蕴意深远的格言，但又不仅以它的说服力取胜，而且还由于在这一深沉的慨叹之中，凝聚了诗人无限的愤懑和真挚的同情。 诗人在阐明上述的内容时，不是空洞抽象地叙说和议论，而是采用鲜明的形象和深刻的对比来揭露问题和说明道理，这就使人很容易接受和理解。 作者在前两句并没有说农民种田怎样辛苦，庄稼的长成如何不易，只是把农民在烈日之下锄禾而汗流不止的情节作了一番形象的渲染，就使人把这种辛苦和不易品味得更加具体、深刻且真实。所以诗人最后用反问语气道出“谁知盘中餐，粒粒皆辛苦”的道理就很有说服力。尤其是把粒粒粮食比作滴滴汗水，真是体微察细，形象而贴切。
Error message is the first step to troubleshoot Apache Cassandra issues. That can help us identify if the issue happens on client-side or server-side. Here are the 4 most common Cassandra issues below. Check Cassandra SyntaxError (client) This and other QueryValidationException indicate that the client sent a malformed request. These are rarely server issues and …
We need to add open source Apache node to dse cluster first. After the data sync is done, we can remove dse nodes. Here are the steps about how to add Apache nodes to dse cluster. Version matches please make sure you Install same version OSS Cassandra with your DSE SELECT release_version FROM system.local; release_version …
CREATE USER in Cassandra CREATE USER alice WITH PASSWORD ‘password_a’ SUPERUSER; CREATE USER bob WITH PASSWORD ‘password_b’ NOSUPERUSER; CREATE USER is equivalent to CREATE ROLE where the LOGIN option is true. So, the following pairs of statements are equivalent: CREATE USER alice WITH PASSWORD ‘password_a’ NOSUPERUSER; CREATE ROLE alice WITH PASSWORD = ‘password_a’ AND LOGIN …
No space left on device usually means that we run out of disk space. But in rare cases, we still have some space when we get this error. People will get confused when they get this error. Here is the troubleshooting process about this. “No space left on device” even though there is space # …
Rsync is a unique, full-featured file transfer facility. It can perform differential uploads and downloads (synchronization) of files across the network, transferring only data that has changed. How does Rsync work? Rsync faster than scp or sftp? How to use Rsync to sync files between servers? For example, if there is a local copy of …
No Load balancers in front of cassandra Cassandra distributes the data across the nodes and most of the cassandra drivers have the algorithm built in to direct requests appropriately . Adding load balancer introduces an additional layer , potentially breaks intelligent algorithms used by driver and also introduces a single point of failure where there …
Decrease the default read ahead values in unix/linux systems Most of the modern unix/linux systems use read ahead so that subsequent reads will be cached in to memory . This provides a performance benefit for systems that read data sequentially (e.g. Kafka) .However, in cassandra most normal read operations are not sequential and hence read …