what is fast cache in vnx

Is fast cache VNX secure?

FAST Cache Internals. FAST Cache is built on the ‘Unified LUN’ technology; thus the Data in FAST Cache is as secure as any other LUN in the CX/VNX array. FAST Cache is a nonvolatile storage that survives both power and SP failures and it does not have to re-warm after a power outage either.

What is the difference between fast cache and fast VP?

First of all, FAST Cache you set up on Storage System level, so everything provisioned on the Storage Array can take an advantage, both RAID LUNs and pool LUNs. FAST VP is created in a Storage Pool, and can be used only for LUNs within that Storage Pool. Take a look at comparison created by EMC to see all the main differences. FAST CACHE FAST VP

What is ‘fast cache’ technology?

EMC ‘FAST Cache’ technology gives a performance enhancement to the VNX Storage Array by adding FLASH drives as a Secondary Cache, working hand-in-hand with DRAM Cache and enhancing overall Storage Array performance.

How secure is fast cache?

FAST Cache Internals. FAST Cache is built on the ‘Unified LUN’ technology; thus the Data in FAST Cache is as secure as any other LUN in the CX/VNX array.

What is fast cache?

FAST Cache is a high capacity secondary cache which logically sits below System Cache, and above the drives in the system. FAST Cache complements the System Cache by using Flash drives to service highly active data being requested from the drives.

WHAT IS FAST VP in Vnx?

FAST VP differentiates each of these tiers by drive type, but it does not take rotational speed into consideration. EMC strongly encourages that you avoid mixing rotational speeds per drive type in a given pool. If multiple rotational-speed drives exist in the array, you should implement multiple pools as well.

What does FAST cache reduce?

With a compatible workload; FAST Cache increases performance by reducing the response time to hosts and provides higher throughput (IOPS) for busy areas that may be under pressure from drive or RAID limitations.

What is storage processor in Vnx?

Storage Processors (SPs) support block data with UltraFlex I/O technology that supports Fibre Channel, iSCSI, and FCoE protocols. The SPs provide access for all external hosts and the file components of the VNX array. • The Storage Processor Enclosure (SPE) is 4U in size and houses dual storage processors.

WHAT IS FAST VP and FAST cache?

EMC VNX – FAST Cache vs FAST VPFAST CACHEFAST VPAllows Flash drives to be used to extend the existing caching capacity of the whole storage systemAllows a single LUN to leverage the advantages of multiple drive types through the use of storage pools.Granularity is 64 KBGranularity is 1 GB4 more rows•Sep 4, 2014

What is fast in EMC?

FAST Cache utilizes flash drives as an additional cache layer within the system to temporarily store highly accessed data. It can only be created with SAS Flash 2 drives and is only applicable to hybrid pools.

What are the 3 types of cache memory?

Types of cache memoryL1 cache, or primary cache, is extremely fast but relatively small, and is usually embedded in the processor chip as CPU cache.L2 cache, or secondary cache, is often more capacious than L1. ... Level 3 (L3) cache is specialized memory developed to improve the performance of L1 and L2.

What is L1 L2 and L3 cache?

Cache is graded as Level 1 (L1), Level 2 (L2) and Level 3 (L3): L1 is usually part of the CPU chip itself and is both the smallest and the fastest to access. Its size is often restricted to between 8 KB and 64 KB. L2 and L3 caches are bigger than L1. They are extra caches built between the CPU and the RAM.

Is it good to delete cache?

Clearing your cache on Android can free up valuable space and resolve issues with your phone's battery, speed, and security. Old cached data can corrupt, causing larger performance problems. If a particular app receives an update, the cached data from a previous version can cause conflict.

What is the use of control station in Vnx?

Control Station – CS – Normally preceded by “Primary” or “Secondary” as there are at least 1, but most often 2 control stations per VNX system. It is the job of the control station to handle management of the File or Unified components in a VNX system. Block only VNX arrays do not utilize a control station.

What is DPE in EMC?

The Disk Processor Enclosure contains the actual working parts of the EMC device – all the stuff related to block-level protocols. It's also where the Vault Drives of your device can be found.

What is SLIC in storage?

SLIC means Scheduling and Logging system for the CAISO.

Does clearing cache delete passwords?

If you saved passwords in your browser so you could automatically log in to certain sites, clearing your cache can clear your passwords as well.

What does clearing your phone cache do?

When you use a browser, like Chrome, it saves some information from websites in its cache and cookies. Clearing them fixes certain problems, like loading or formatting issues on sites.

What happens when you clear your browser cache?

After you clear cache and cookies: Some settings on sites get deleted. For example, if you were signed in, you'll need to sign in again. If you turn sync on in Chrome, you'll stay signed into the Google Account you're syncing to in order to delete your data across all your devices.

What makes cache faster?

Cache memory holds frequently used instructions/data which the processor may require next and it is faster access memory than RAM, since it is on the same chip as the processor. This reduces the need for frequent slower memory retrievals from main memory, which may otherwise keep the CPU waiting.

How does fast cache work?

With a compatible workload; FAST Cache increases performance by reducing the response time to hosts and provides higher throughput (IOPS) for busy areas that may be under pressure from drive or RAID limitations. Apart from ‘Storage Processors’ being able to cache read and write I/Os; the Storage Processors on the VNX also coalesce writes and pre-fetch reads to improve performance. However, these operations generally do not accelerate random read-heavy I/Os and this is where FAST Cache helps. FAST Cache monitors the storage processors’ I/O activity for blocks that are read or written to multiple times , with the third IO to any block within a 64K extent getting scheduled for promotion to FAST Cache, promotion is handled the same way as writing or reading an IO to a LUN. The migration process operates 24×7 using the ‘Least Recently Used algorithm’ in order to determine which data stays and which goes. The writes continue to be written to DRAM write cache but with FAST Cache enabled those writes are flushed to the Flash drives and so increasing flush speeds.

What is a fast cache SSD?

FAST Cache SSD – These are single-level cell (SLC) Flash drives that are targeted for use with FAST Cache . These drives are available in 100GB and 200GB capacities and can be used both as FAST Cache and as TIER-1 drives in a storage pool.

What is EMC Fast Cache?

EMC FAST Cache technology gives a performance enhancement to the VNX Storage Array by adding FLASH drives as a Secondary Cache, working hand-in-hand with DRAM Cache and enhancing overall Storage Array performance. EMC recommend firstly using available Flash Drives for FAST Cache and then adding Flash Drives as a tier to selected FAST VP pools as required. FAST Cache works with all VNX systems (And also CX4) and is activated by installing the required FAST Cache Enabler. FAST Cache works with traditional Flare LUNs and VP Pools.

How many fast cache drives per bus?

Amount of FAST Cache drives per B/E Bus differs for each system but ideally for a CX/VNX1 system aim for no more than 4 drives per bus and 8 for a VNX2. It is best practice on a CX/VNX1 to avoid placing drives on the DPE or 0_0 that will result in one of the drives being placed in another DAE, for example DO NOT mirror a drive in 0_0 with a drive in 1_0.

Is Fast Cache a nonvolatile storage?

FAST Cache is built on the Unified LUN technology; thus the Data in FAST Cache is as secure as any other LUN in the CX/VNX array. FAST Cache is a nonvolatile storage that survives both power and SP failures and it does not have to re-warm after a power outage either.

Does Fast Cache need to be disabled?

Note: FAST Cache configuration requires any modification then it first needs to be disabled. By disabling (destroying) FAST Cache all dirty blocks are flushed back to disk; once FAST Cache has completed disabling then you may re-create FAST Cache with your new configuration.

Is Fast Cache selective?

Note: FAST Cache is enabled at the Pool wide level and cannot be selective for specific LUNs within the Pool.

What happens when you disable Fast Cache?

By disabling (destroying) FAST Cache all dirty blocks are flushed back to disk; once FAST Cache has completed disabling then you may re-create FAST Cache with your new configuration.

Is Fast Cache selective?

Note: FAST Cache is enabled at the Pool wide level and cannot be selective for specific LUNs within the Pool.

What is fast cache?

Multicore FAST Cache allows you to leverage the lower response time and better IOPS of Flash drives without dedicating Flash drives to specific applications. This technology supplements the available storage-system cache (adding up to 4.8 TB read/write Multicore FAST Cache in the VNX7600 and VNX8000 storage systems; see

What is a fast cache promotion?

Multicore FAST Cache promotion is the process in which data is copied from spinning media HDDs and placed into Multicore FAST Cache. The process is defined as a promotion due to the upgrade in performance the data receives from being copied from spinning media to Flash technology.

What is multicore cache?

Multicore Cache complements Multicore FAST Cache by handling certain I/O patterns that may not benefit from the use of Multicore FAST Cache. For example, small-block sequential I/O is handled at the Multicore Cache level, which means cycles are not spent copying data into Multicore FAST Cache that may not be used again. For example, small-block sequential writes will coalesce into larger I/Os to the HDDs, and small-block sequential reads will cause prefetching to occur. In both cases, larger back-end I/Os are created which may not cause the data being accessed to be promoted into Multicore FAST Cache. Multicore Cache also handles high-frequency access patterns, zero fill requests, and I/Os that are larger than 128 KB in size. Multicore Cache acts as a filter for Multicore FAST Cache, which provides more cycles to copy data into Multicore FAST Cache that will benefit from the use of it.

Why use multicore fast cache?

One of the major benefits of using Multicore FAST Cache is the improved application performance, especially for workloads with frequent and unpredictable large increases in I/O activity . The part of an application’s working dataset that is frequently accessed is copied to the Multicore FAST Cache, so the application receives an immediate performance boost. Multicore FAST Cache enables applications to deliver consistent performance by absorbing bursts of read/write loads at Flash drive speeds.

What is a fast vp?

Fully Automated Storage Tiering for Virtual Pools (FAST VP) is a feature that performs storage tiering for 256 MB slices of data at a sub-LUN level in pools that contain multiple drive types. FAST VP automatically moves more active slices (data that is more frequently accessed) to the best performing storage tier, and it moves less active slices to a lower performing (and less expensive) tier for a better TCO. For more details on this feature, refer to the EMC VNX FAST VP white paper available on EMC Online Support.

How does FAST cache work?

Data on LUNs that becomes busy is promoted to FAST cache. The promotions depends on the number of accesses (read and/or write) within a 64KB chunk of storage, and is not dependent on whether the data already exists in the DRAM cache. If you have FAST VP I/Os from extreme performance tier are not promoted to FAST Cache.

What happens when a host I/O request is a write operation for a data chunk in Fast Cache?

If the host I/O request is a write operation for a data chunk in FAST Cache, and the write cache is not disabled for the LUN, the DRAM cache is updated with the new “write”, and an acknowledgment is sent back to the host. The host data is not written directly to the FAST Cache. When data needs to be moved out of the DRAM Cache, it is written to FAST Cache.