ACID (atomicity, consistency, isolation, and durability)
ACID (atomicity, consistency, isolation, and durability) is an acronym and mnemonicdevice for learning and remembering the four primary attributes ensured to any transaction by a transaction manager (which is also called a transaction monitor). These attributes are:
Atomicity. In a transaction involving two or more discrete pieces of information, either all of the pieces are committed or none are.
Consistency. A transaction either c...
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SQL (Structured Query Language)
SQL (Structured Query Language)
SQL (Structured Query Language) is a standardized programming language used for managing relational databases and performing various operations on the data in them. Initially created in the 1970s, SQL is regularly used by database administrators, as well as by developers writing data integration scripts and data analysts looking to set up and run analytical queries.
The uses of SQL include modifying database table and index structures; adding, updating and...
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Database Management System (DBMS)
Database Management System (DBMS)
A database management system (DBMS) is system software for creating and managing databases. The DBMS provides users and programmers with a systematic way to create, retrieve, update and manage data.
A DBMS makes it possible for end users to create, read, update and delete data in a database. The DBMS essentially serves as an interface between the database and end users or application programs, ensuring that data is consistently organized and remains easily a...
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RAID Definition
RAID Definition
Stands for "Redundant Array of Independent Disks." RAID is a method of storing data on multiple hard disks. When disks are arranged in a RAID configuration, the computer sees them all as one large disk. However, they operate much more efficiently than a single hard drive. Since the data is spread out over multiple disks, the reading and writing operations can take place on multiple disks at once. This can speed up hard drive access time significantly. Multiple hard drives may no...
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EMC VNX – RAID groups vs Storage Pools
EMC VNX – RAID groups vs Storage Pools
With EMC training I have learnt some general guidelines, that should be followed to optimize and enable good performance on a VNX Unified storage system.
Drive types
When you chose a specific drive type, you should base your choice upon the expected workload.
FLASH – Extreme Performance Tier – great for extreme performance.
SAS – Performance Tier – perfect for general performance. Usually 10k RPM or 15k RPM.
NL-SAS – Capacity Tier – most cos...
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what is FAST Cache?
what is FAST Cache?
You can compare FAST Cache as a “DRAM cache” but built from FLASH drives, with higher capacity available. Let’s start at the beginning:
DRAM cache – is a storage-system component that improves performance by transparently storing data in very fast storage media (DRAM). It’s capacity is limited and very expensive.
FAST cache technology supplements the available storage-system cache (DRAM cache), adding up to 2 TB read/write FAST Cache. The nice trick is that FAST Cache...
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EMC VNX FAST VP Definition
EMC VNX FAST VP Definition
FAST VP stands for Fully Automated Storage Tiering for Virtual Pools. It’s a very smart solution for dynamically matching storage requirements with changes in the frequency of data access. FAST VP segregates disk drives into three categories (already explained in EMC VNX – RAID groups vs Storage Pools) called tiers:
Extreme Performance Tier – Flash drives
Performance Tier – 15k and 10k SAS drives
Capacity Tier – Near-line SAS drives (that can be up to 4TB i...
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EMC VNX VG8 Gateway
EMC VNX VG8 Gateway
The EMC VNX VG8 platform extends the value of existing EMC storage array technologies. It delivers a comprehensive, consolidated solution that adds NAS storage in a centrally managed information storage system, enabling you to dynamically grow, share, and cost effectively manage file systems with multi-protocol file access. If you are looking for a massively scalable EMC IP storage solution to extend your esisting storage investment, or want a enterprise, SAN-...
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EMC VNX VG2 Gateway
EMC VNX VG2 Gateway
The EMC VNX VG2 platform extends the value of existing EMC storage array technologies. It delivers a comprehensive, consolidated solution that adds NAS storage in a centrally managed information storage system, enabling you to dynamically grow, share, and cost effectively manage file systems with multi-protocol file access. If you are looking for an entry-level EMC IP storage solution to extend your esisting storage investment, or want a low-cost, SAN- plus-NAS p...
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EMC Unisphere
EMC Unisphere
EMC Unisphere: a simple, integrated experience for managing EMC VNX Family, EMC CLARiiON, and EMC Celerra storage systems through both a storage and virtualization lens. It’s designed to provide simplicity, flexibility, and automation—key requirements for the journey to the cloud.
Unified Management
Unisphere delivers a common experience with a single interface for managing file, block, object and replication across VNX Series, CLARiiON and Celerra system...
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