最近在思考和实践怎样应用重复数据删除技术到云存储服务中.找了些论文来读,其中<Avoiding the Disk Bottleneck in the Data Domain Deduplication File System>是鼎鼎大名的李凯教授出品,读来收益匪浅. 论文主要内容 Data Domain的去重存储系统是商业上大获成功的产品,从产品的角度来讲非常完善,其架构图如下: 去重存储系统在数据存储和重建的过程中,都需要频繁地访问数据块的索引,即图中的Segment Index.为了降低成…

1.磁盘基础知识 1.1 物理结构 硬盘的物理结构一般由磁头与碟片.电动机.主控芯片与排线等部件组成:当主电动机带动碟片旋转时,副电动机带动一组(磁头)到相对应的碟片上并确定读取正面还是反面的碟面,磁头悬浮在碟面上画出一个与碟片同心的圆形轨道(磁轨或称柱面),这时由磁头的磁感线圈感应碟面上的磁性与使用硬盘厂商指定的读取时间或数据间隔定位扇区,从而得到该扇区的数据内容.所有的盘片都固定在一个旋转轴上,这个轴即盘片主轴.而所有盘片之间是绝对平行的,在每个盘片的存储面上都有一个磁头,磁头与盘片之间的距…

https://hadoop.apache.org/docs/r2.7.2/hadoop-project-dist/hadoop-hdfs/HdfsDesign.html Introduction [相对于POSIX,放宽要求] The Hadoop Distributed File System (HDFS) is a distributed file system designed to run on commodity hardware. It has many similarities…

參考文献: Harley Hahns:Guide to Unix and Linux. Chap 24 -->首先要有的关键概念:the amount of "disk space" used by a file is not the same as the amount of data in the file. -->其次,理解在file system和disk(or other storage medium)中都存在各自的最小空间单元:file system中叫&quo…

File System Function In computing, a file system or filesystem is used to control how data is stored and retrieved. Without a file system, information placed in a storage medium would be one large body of data with no way to tell where one piece of i…

In NetSuite SuiteScript, We usually do/implement export data to CSV, that's straight forward: Collect 'encoded' string to Array for column, join them with comma ',' to be a string. Collect each line's data same as column to push to the Array. Join al…

EMC 數據清空 1.數據清空 這裡會清空file system的所有東西包括tapes…

今天在做mkdir操作时报错:Invalid file system control data detected.检查用户和权限没问题,再检查磁盘空间也没问题.最后在网上找到如下信息: [problem] # mkdir aaa mkdir: 0653-358 Cannot create aaa. aaa: Invalid file system control data detected. [solution] usually the reasons is corrupt inodes etc…

BW数据库后台报错如下:F:\oracle\SBP\saptrace\diag\rdbms\sbp\sbp\trace ORA-01578: ORACLE data block corrupted (file # 29, block # 2889087)ORA-01110: data file 29: 'G:\ORACLE\SBP\SAPDATA2\SR3_18\SR3.DATA18'ORA-26040: Data block was loaded using the NOLOGGING opt…

Use  Poi.jar Import Data from *.xlsx file to DB Table through OAF page Use Jxl.jar Import Data from Excel sheet to DB Table through OAF page…

在eclipse打开的android虚拟手机,打开File Explorer,下面是空的没有data.mnt.system三个文件 这是因为模拟器没有选择打开的缘故,必须首先打开一个模拟器(AVD),然后在左侧选择模拟器,右边才会出现相应的mnt等文件夹! 当我们启动起来模拟器后, 然后进入DDMS,在file Explorer中看到下面…

OBLIVIATE redesigned ORAM for SGX filesystem operations for confuse access patterns to protect user privacy. Why All existing SGX filesystems are vulnerable to system call snooping, page fault, or cache based side-channel attacks. How Run isolated fi…

Ubuntu : Status 14: The disk contains an unclean file system By mkyong | July 23, 2014 | Viewed : 10,649 times +47 pv/w Dual boot Windows and Ubuntu, but Ubuntu is unable to access the Windows partition /dev/sdb3, shows the following error message :…

警告日志中发现如下报错信息: ORA-01578: ORACLE data block corrupted (file # 3, block # 1675)ORA-01110: data file 3: '/u01/app/oracle/oradata/PROD1/undotbs01.dbf' 报错提示为:undo表空间第1675个数据块出现损坏. 解决方法: 1.创建新的undo表空间undotbs2 SQL> create undo tablespace UNDOTBS2 datafile…

To demonstrate the difference between mutability and immutability, imagine taking a drink from a glass of water. If our glass is mutable, when we take a drink, we retain the same glass and change the amount of water in that glass. However, if our gla…

DDR PHY interface bit error testing and training is provided for Double Data Rate memory systems. An integrated circuit comprises a bit error test (BERT) controller that provides a bit pattern; and a physical interface having a plurality of byte lane…

所需组件: microsoft ado ext. 2.8 for ddl and security 或者更新的组件. 添加: using ADOX;using System.Runtime.InteropServices;using System.IO; 然后利用OleDbCommand组件,设置其2个链接,一个链接负责查找并打开excel数据源,另一个链接负责将数据源插入到MDB文件中. 操作页面: 后台源码: private void button1_Click(object sender,…

1      Problem Description The field reports show that xxx panel will lockup and then reboot while doing security port scan by nmap. 2      Root Cause After analysis, this problem happens at all panel versions, standalone/networking panel, and happen…

package com.android.utils; import java.io.File; import java.io.IOException; import java.io.RandomAccessFile; import java.util.Arrays; import android.app.Activity; import android.util.Log; /** * 在一些对数据实时性要求比较高的场合,如随时可能断电的场合下,同时需要将数据写入文件中, * 这个时候,我们不希望…

  1,程序中使用加载反射出现下面的问题: 无法加载一个或多个请求的类型.有关更多信息,请检索 LoaderExceptions 属性. 然后把代码改了一下, try { types.AddRange(assembly.GetTypes()); } catch (Exception e) { var assemblyName = assembly.FullName; if (e is System.Reflection.ReflectionTypeLoadException) { var typ…

原文:http://pimin.net/archives/432 环境:Eclipse LUNA.Spring 4.1.1.或Spring 4.3.3.Spring Data Elasticsearch 1.1.0 缘由:在调试Spring Data Elasticsearch的时候,希望在查询的时候实现分页查询.传统的方式就是在Controller的参数表中自己获取分页信息,然后组装成Pageable.在Spring Data Elasticsearch官方文档介绍有两种自动化方案: 1.使用…

Install: pip install pandas pip install matplotlib # check out the doc from site import pandas as pd import matplotlib.pyplot as plt from numpy import mean def load_df(symbol): return pd.read_csv("data/{0}.csv".format(symbol)) def get_max_close(…

猜测,是因FTP服务器采用了主动模式,在创建数据传输通道时,服务器会以一个随机的端口,连接回来. 临时解决方案: 因不知道请求回来使用的哪个段的端口,因此,暂时关闭了防火墙.即能正常传输文件了.…

Raw File Source & Raw File Destination一般用在当有某个package在导入数据或者处理数据需要花费非常长的时间的情况下,可以通过把一些处理好的数据先存到raw file里面,避免出现遇到错误而需要再重新来过的风险,起码可以去Raw file source里面找到数据而不需要从头开始.…

$filedata = @' app.name=Test App app.version=1.2 '@ $filedata | set-content appdata.txt $AppProps = convertfrom-stringdata (get-content ./appdata.txt -Raw) $AppProps…

GFS Key Components components failures are a norm even space utilisation write-once-read-many GFS and Hadoop Distributed File System GFS主要分为:Application .Master.ChannelServer hdfs主要分为:Appllcation . NameNode .DataNode三部分 how to read file from hdfs HDF…

On the internet you will find plenty of tools for checking disk space utilization in Linux. However, Linux has a strong built in utility called ‘df‘. The ‘df‘ command stand for “disk filesystem“, it is used to get full summary of available and used d…

Doc ID 428681.1 Applies to: Oracle Database - Enterprise Edition - Version 10.2.0.1 to 11.2.0.1.0 [Release 10.2 to 11.2]Information in this document applies to any platform. Goal The goal of this note is to provide steps to add, remove, replace or mo…

[root@node1 ~]# df -hFilesystem Size Used Avail Use% Mounted on/dev/mapper/centos-root 26G 17G 9.8G 63% / ★totally 26Gdevtmpfs 1.4G 0 1.4G 0% /devtmpfs 1.4G 0 1.4G 0% /dev/shmtmpfs 1.4G 8.8M 1.4G 1% /runtmpfs 1.4G 0 1.4G 0% /sys/fs/cgroup/dev/sda1 10…

科普链接:https://wiki.archlinux.org/index.php/Disk_encryption 前面的链接关于硬盘加密,讲了几种,基本上就是选dm-crypt with LUKS 在grub中,解密根分区以及/boot分区. dm-crypt文档:https://wiki.archlinux.org/index.php/Dm-crypt 使用 dm-crypt加密一个非根分区.https://wiki.archlinux.org/index.php/Dm-crypt/Encr…