The RAID controller has two options for handling upper-level write IO, as follows:   1.WriteBack mode: when the data is sent from the upper layer, the RAID controller will inform the host that I0 has completed immediately after saving it in the cache, so that the host can execute the next IO without waiting. At this time, the data is in the cache of the RAID controller card, but not really written to the disk, which plays a buffer role. The RAID controller waits for the time to be idle and either writes to disk one by one, or writes to disk in bulk, or queues the IO (similar to the queuing technique on disk) for some optimization algorithm to write to disk efficiently. Because the disk write speed is slow, the RAID controller in this case deceives the host, but gains high speed, which is "keep the easy to the top, keep the trouble to yourself." This has a fatal shortcoming, that is, once the power fails unexpectedly, the data in the cache on the RAID card will all be lost, and at this time the host thinks that IO has completed, so the upper and lower layers will produce inconsistency, the consequences will be very serious. As a result, critical applications such as databases have their own measures of consistency. Because of this, the high-end RAID card needs to use the battery to protect the cache, so that in the case of accidental power down, the battery can continue to power the cache to ensure that the data is not lost. When powered up again, the RAID card will first write the outstanding IO from the cache to disk. 2.WriteThrough mode: This is the writethrough mode, i.e., the top IO. Only after the data has actually been written to disk by the RAID controller will the host be notified of the completion of IO, which ensures high reliability. In this case, the cache's speedup is no longer beneficial, but its buffering is still effective. In addition to being a write cache, the read cache is also very important. Caching is a complex subject and has a complex mechanism, one of which is called PreFctch, or prefetching, which reads data on disk that are "likely" to be accessed by the host next into the cache before the host has issued a read IO request. How do we calculate the possibility? In fact, it is considered that the next time the host IO, there is a large rate of children will read the data in the disk location adjacent to the data read this time. This assumption is very useful for IO sequential reads, such as reading data that is logically contiguous, such as FTP large file transfer services, video on demand services, and so on, which are large file reading applications. On the other hand, if many small files are also stored contiguously on disk, caching will greatly improve performance, because reading small files requires a high IOPS, and without caching, it will take a long time to rely on the head seek to complete IO each time. There is also a caching algorithm, which is not based on prefetching, but on the assumption that the next time the host does IO, it may also read the data from the last or several (recent) reads. This assumption is completely different from prefetching. After the RAID controller reads a piece of data into the cache, if the data is changed by the host's write IO, the controller does not immediately write it to disk for storage. It stays in the cache, because it assumes that the host may read the data again in the near future. Then there is no need to write to disk and delete the cache, and then wait for the host to read, and then read from the disk to the cache, it is better to static brake, simply stay in the cache, wait for the host to "toss" the frequency is not high, then write to disk. Tips：Medium and high end RAID cards generally have more than 256MB of RAM as cache. Unleash the power of RAID Experience high performance data storage with our advanced RAID cards. Trust our 10 + years of expertise.STOR Technology Limited will also provide you with a large number of original high-performance products, such as: lsi 9480 8i8e, lsi 9361 4i, lsi 9341 8i and so on, three-year warranty and unsurpassed factory price to reduce your concerns.

LSI 9460-16i is a RAID controller card. Its specifications and advantages have been introduced to you before. Next, I will briefly describe its application and precautions: Application: Enterprise Storage Environment: Megaraid 9460-16i is suitable for storage solutions in medium to large enterprise environments. Because it supports multiple internal SAS/SATA ports, it can manage large-capacity internal disk arrays and provide reliable data storage and high-performance access for enterprises. Data center environment: In the data center, the 9460-16i can scale storage capacity and provide high performance data storage and access. It can support multiple storage devices, and has a powerful RAID function to ensure data integrity and availability. Virtualized environments: For virtualized environments, the megaraid sas 9460-16i provides high performance and reliable storage management. It supports the storage requirements of multiple virtual machines and enables appropriate RAID configuration as needed to ensure the stability and performance of the virtualized environment. Notes: Compatibility: When choosing an LSI 9460-16i 05-50011-00, make sure it is compatible with your server or storage device. Check the manufacturer's compatibility list to confirm that the RAID controller you choose is compatible with your system's hardware and software environment. Cold and hot backups: To ensure data security and high availability, consider configuring cold or hot backups. Cold backup is to keep a backup disk array to back up data, and hot backup is to generate backup copies in real time to provide fast recovery. These policies help mitigate the risk of hardware failure or data loss. Regular monitoring and Maintenance: It is important to regularly monitor the condition of the LSI 9460-16i controller and disk array. Checking logs, performing disk checks, and updating firmware and drivers in a timely manner are key steps to ensure controller stability and performance. Data backup: Although the RAID controller provides some level of data protection, it is still recommended to take regular data backup. Data loss can occur due to RAID controller failure, multiple disk failure, and accidental deletion. Therefore, it is very important to back up your data regularly. The above is the general application and precautions. Specific applications and considerations may vary depending on your environment and requirements. Of course, we will be happy to answer your questions, and believe that with STOR Technology Limited professional experience and strength, we can provide you with the required high-performance products.

LSI 9361-16i is a RAID controller card produced by Broadcom, which is widely used in enterprise storage systems and servers. Let me briefly introduce some common specifications and advantages of the LSI 9361-16i ( 05-25708-00 ):   Specification: 1. Interface: PCIe 3.0x8 (backward compatible with PCIe 2.0)   2.Ports: 16 internal SAS/SATA ports   3.RAID level support: RAID 0, RAID 1, RAID 10, RAID 5, RAID 50, RAID 6, RAID 60   4. Storage capacity expansion: supports up to 256 physical devices   5. Memory: 1GB 1866 MHz DDR3 SDRAM (upgradeable to 4GB)   Advantages: 1. High performance: Megaraid sas 9361-16i has powerful processing power and data throughput, which can provide excellent performance and is suitable for high load storage environment.   2. Resilience and flexibility: Multiple RAID levels are supported to meet different data protection and performance requirements. It also supports hybrid drive types, including SAS and SATA, providing greater storage flexibility.   3. Data protection and reliability: 9361 16i has a variety of data protection functions, such as RAID level failure protection, hot backup, bad track repair and data encryption, to ensure data security and integrity.   4. Management and monitoring functions: the supporting management software (such as MegaRAID Storage Manager) provides rich monitoring and management functions, including remote management, alarm notification, configuration management, etc., to simplify management and maintenance.   5. Scalability: Support multiple LSI 9361-16i cards to expand through SAS link, providing greater storage capacity and performance.   Please note that specific specifications and benefits may vary from product version to product version and vendor changes. For the most accurate information, it is recommended to contact me directly for the latest and detailed product information, and STOR Technology Limited will provide you with the most detailed service and high-performance original products.

  The RAID system is an effective means to protect data from stored data. In the RAID creation process, there is often a very long time system initialization process. Why is there such an operation in the RAID initialization process? What aspects will this operation have on SSD? Let's analyze and study the RAID initialization process from the perspective of technology development.   The basic organizational structure of a traditional RAID array is that all disks added to a RAID Group are divided into a series of slices based on their LBA addresses. These slices are called Stripe Units. Stripe units corresponding to the same LBA addresses on different disks are organized into a Stripe. Encoding all data in one strip, such as RAID6 producing two encoded data blocks P and Q, allows both data disks to be corrupted at the same time.   Therefore, in the RAID system, all the data in the strip need to meet the rules of coding and dec algorithm, that is, all the data in the strip can generate coding data according to certain rules, and the coding data is the same as the coding data stored in the strip. This situation is called the data in that band. When a disk fails, the lost data blocks can be recovered by the encoded data stored in the strip.   If the data in a strip is inconsistent, that is, the coding result obtained by the data in the strip is not the same, then once a disk fails, the missing data block cannot be properly recovered by the coded data stored in the strip. Therefore, a strip of data inconsistency that will cause data correctness issues when the fault occurs. When creating a RAID system, the disk in the RAID Group may be either a new disk or a data disk that has already been used, where all data will not be zero. In this case, the data strips constructed with these disks must not meet the need of data consistency. That is, the coding data in each band calculated according to certain rules is inconsistent with the coding data in the band. Such data-inconsistent bands will introduce a great risk to the problem of RAID data correctness.   For this reason, when creating a RAID, you need to consider initializing all the strips in the system to ensure the consistency of the data in the bands. Band initialization can usually be solved in two ways: 1. Initializes all the bands in the RAID system by writing the total zero. All data zero band, its check data is also zero. Therefore, all-zero data can guarantee band consistency. 2. Check all the strips and update the check data in the strips to achieve the consistency of the strip data.   When a RAID system is initialized, the data in all bands will become consistent.The RAID system initialization process is a very long process, mainly because the need to initialize all the bands in the system. The performance balance between the front-end user IO, so RAID system initialization is often a background execution process, which will last for a long time and affect the performance of front-end applications.   For SSDS, the RAID system initialization process also introduces other problems. During system initialization, data needs to be written to SSDS, no matter in zero write or parity data update mode. This process results in unnecessary data write enlargement. Before user data is written, a data mapping table is established inside the SSD through initialization. The service life and performance of SSDS are reduced. Therefore, a RAID system for SSDS needs to be optimized for the system initialization process, which is a special feature that traditional RAID does not take into account. Therefore, traditional RAID arrays cannot be directly deployed on SSDS, which affects SSD service life and performance.   RAID systems use striping to protect data, but a series of problems are also introduced in the process of striping data protection. System initialization is a typical problem of strip consistency. A good RAID Data protection system will solve this problem during the design process. For example, EMC Data Domain RAID does not have the system initialization process, of course, it needs to cooperate with the file system, and has done a lot of optimization in RAID strip data distribution.