nas raid5

Principle of RAID5 Data recovery algorithmTo understand the principle of RAID5 data recovery first to know RAID5, "distributed parity of the independent disk structure" is what we call the RAID5 data recovery has a concept to understand, that is, "parity check." We can simply understand it as an "XOR operation" in bina

following information when the system posts:Dell PowerEdge Expandable RAID Controller 3/di, BIOS v2.7-x [build xxxx] (c) 1998-2002 Adaptec, Inc. All Rights Reserved. If you have a AMI/LSI disk array controller (PERC2/SC,PERC2/DC,PERC3/SC,PERC3/DC, Perc4/di, PERC4/DC), you will see the following information when the system posts:Dell PowerEdge Expandable RAID Controller BIOS x.xx June 26.2001 Copyright (C) American Megatrends Inc.Press Ctrl+m to Run Configuration Utility or press ctrl+h for We

[Data recovery failure description] A government organization in Xinjiang, MS SQL Server server, the hardware environment is: IBM X225, composed of 4 73G SCSI hard drives in the Raid5,raid only one logical volume is divided. The operating system is Windows 2003. A, did not find a fault before, until the server is paralyzed, and then check the server, found 3 hard drives offline. B, arbitrarily forced online 2 hard drive, unable to start the operati

Reference Document http://www.cnblogs.com/ivictor/p/6099807.htmlMaking RAID5 http://blog.51cto.com/11134648/2103384RAID0also known as stripe or striping, it represents the highest storage performance in all RAID levels. RAID 0 improves storage performance by spreading continuous data across multiple disks, so that the system has data requests that can be executed in parallel by multiple disks, each of which performs its own portion of the data request

array here, while RAID 0 is responsible for reading and writing the data array. In fact, the right image is just a raid 10 way, more cases are separated from the main channel two, do striping operation, that is, the data segmentation, and this points out each road is divided into two ways, do mirroring operation, that is, mirror each other. Use: 4 disk For example, 2 pairs of raid, RAID 0 raidAdvantages: Improve read and write, redundant, each pair of RAID1 can bad piece Virtual impl

It was with the previous reading and writing base that we began to look at the RAID5D code. RAID5D is not a read-write entry, nor is it a place to read and write, but simply a transit point or a transport hub. The hub has a commanding position, like the U.S. base in Singapore, which directly controls the transport hubs in the Pacific and Indian Oceans. 4626/* 4627 * This is RAID5 kernel thread. 4628 * 4629 * We scan the hash table for stripes whic

Server I told a story of the background is this, in a certain POS project using SQL SERVER 2000 to do the foreground database, IBM's DB2 do background database. The environment for the foreground database is such that the operating system is Windows Server (USERS), and the database is SQL Server (E) +sp3,application is a POS system (a real-time trading system). Hardware configuration is: P4 xron 2.4g*2,36g hdd*5 RAID5, 1G memory,hp tape drive, the dat

EAD----delete--files/sec%cp/sec%cp/sec%cp/sec %cp/sec%cp/sec%CP 1 +++++ +++ 161 1 Bayi 1 +++++ +++ 163 1jump,8g,12647,36,13414,8,7952,13,33636,97,146503,71,465 .7,5,16,86,1,+++++,+++,161,1,81,1,+++++,+++,163,1 4 disk RAID5, disable write cache speed: #./bonnie++-d/eygle-u root-s 8192-m jumpusing uid:0, gid:1.writing with PUTC () ... donewriting intelligently...d Onerewriting...donereading with getc () ... donereading intelligently...donestart ' Em.

To prepare the operation:1, centos7.2 RAID 5 experimental detailedAdd 4 20G hard drives to VMware2, view the hard disk (after the new disk needs to perform partprobe-to make kernel re-read the partition table)[Email protected] ~]# fdisk-ldisk/dev/sdb:21.5 GB, 21474836480 bytes, 41943040 sectorsDevice Boot Start End Blocks Id System/DEV/SDB1 2048 41943039 20970496-up Linuxdisk/dev/sdc:21.5 GB, 21474836480 bytes, 41943040 sectorsDevice Boot Start End Blocks Id System/DEV/SDC1 2048 41943039 2097049

started.[Root @ centos/] #2. create a file system as ext3[Root @ centos/] # mkfs. ext3/dev/md0Create directory/mnt/raid and Mount[Root @ centos/] # mkdir/mnt/raid[Root @ centos/] # mount/dev/md0/mnt/raid3. understand raid status[Root @ centos/] # mdadm-D/dev/md04. start and stopBefore stopping, you need umount and then mdadm? S/dev/md0Start: [root @ centos/] # mdadm-A/dev/md0/dev/sda1/dev/sdb1/dev/sdc1/dev/sdd1If a configuration file has been created, run the command mdadm? As/dev/md05. about t

use of more than a solution.For example, RAID 5, which consists of four hard disks, is stored as shown in the picture in the overview: The P0 is the parity information for D0, D1, and D2, and so on. As can be seen from the figure, RAID 5 does not back up the stored data, but instead stores the data and its corresponding parity information on each disk that makes up the RAID5, and the parity information and the corresponding data are stored on separat

(except that the offset address is different ). Check the HDD and find that the first HDD in RAID5 has a red light (too much dust, it is difficult to see clearly) RunDBCC checkdb ('pos _ db ')Check found:Server: MSG 8909, level 16, state 1, line 1Table error: Object ID 26342838, index ID 35207, page ID (1: 50978). The pageid in the page header = (32230:-2048732002 ). Server: MSG 8939, level 16, state 1, line 1Table error: Object ID 859150106, index

Data security is one of the most important problems people use in computers. Typically, a hard disk mirroring technique is used in a server environment to achieve a dual backup of the data. Also, we can use this technology in a Linux environment. In the Linux environment, the use of raidtools tools, not only can be two hard disk mirroring, but also can make soft RAID0, RAID1, RAID5. Said to be soft raid, because the raid disk is usually done through

/2561410/634725 Server role Zoning recommendations Advantages RAID Programme style= "line-height:150%;font-family: ' song body '; font-size:12pt;" > stand-alone server 8G memory, 300G HDD /boot 100-200M swap16g , memory size 8g*2 /80g /var 20G (not divided) /data 180G (store web and DB data) The data disk is separated from the system disk, which facilitates maintenance when the problem occurs. Depending on t

gain a disk storage system that is more responsive to their requirements by flexibly configuring the disk array. RAID 5E (RAID 5 enhencement): Raid 5E is an improvement over RAID 5 levels, similar to RAID 5, where data is evenly distributed across hard disks, but a portion of unused space is retained on each hard drive, which is not striped. Up to two physical hard drives are allowed to fail. It looks like the raid 5E and RAID 5 plus a hot spare are similar, but because RAID 5E distributes dat

Server: IBM eserver x Series 235 Server Array: IBM EXP300 array Enclosure, IBM Serverraid 4Mx Control card 1, Hardware connection Close the server, install the Serverraid card and connect the Serverraid card with the array cabinet with a dedicated line cable. Boot sequence: First open the array cabinet power, wait for the array cabinet to start, then start the server. IBM Serverraid offers several levels: RAID 0,raid 1,raid 1E, raid5,raid5e. Wher

With the limitations of data security, performance, and capacity on a single disk, disk arrays (redundant Arrays of inexpensive/independent Disks,raid) appear, and RAID combines several separate disks in different ways, Form a disk group to achieve higher data security, performance, and capacity than a single disk.I. Common RAID levelsRAID has several levels of raid0~raid7, plus some composite raid modes, such as: RAID10, RAID01, RAID50, RAID53.The commonly used RAID modes are RAID0, RAID1,

BBU module can go as a power source to ensure that the data is not lost and the data is written to the cache. Now that the new server is the BBU of the capacitive mode, the performance will be better. Questions about the array card policy On the problem of array card strategy, be sure to choose WB (write bike), when writing data, be sure to write to the cache card, and then through the array card to brush the data to disk, so that can improve our iops. Be sure to disable Wthrow, because this d

points per question.1. How does the production scenario properly partition the Linux system?The basic principle of partitioning is simple, easy-to-use and convenient for batch management. The following recommendations are based on server role positioning:① Standalone server: 8G memory, 300G HDDPartition:/boot 100-200m,swap 16G, memory size 8g*2,/80g,/var 20G (also not divided),/data 180G (store web and DB data)Advantage: The data disk and the system disk are separated, which is advantageous to

failure recovery.It is much more difficult to design, and the data access efficiency is not very good.　　RAID5: Independent disk structure of distributed parityIt can be seen from itsThe parity code exists on all disks.Where P0 represents the parity value of The 0th band, and the other meanings are the same.The reading efficiency of RAID5 is very high, the writing efficiency is average, and the block-based