Tài liệu MCSE Windows server 2003- P10 ppt

! Lesson 4 Implementing RAID 11 - 35 Up to 32 disks can participate in a striped volume. The amount of space used on each disk in the volume will be equal to the smallest amount of space on any one disk. For example, if Disk 1 has 200 GB of unallocated space, and Disk 2 has 120 GB of space, the striped volume can contain, at most, 240 GB as the size of the stripe on Disk 1 can be no greater than the size of the stripe on Disk 2. All disk space in the volume is used for data; there is no space used for fault tolerance. Recovering a Striped Volume Because data is striped over more than one physical disk, performance is enhanced, but fault tolerance is decreased—there is more risk because if any one drive in the vol- ume fails, all data on the volume is lost. It is important to have a backup of striped data. If one or more disks in a striped volume fails, you must delete the volume, replace the failed disk(s) and recreate the volume. Then you must restore data from the backup. Exam Tip Striped volumes provide maximum storage and performance but support no fault tolerance. The only recovery potion is that of your regular backup routine. Mirrored Volumes A mirrored volume provides good performance along with excellent fault tolerance. Two disks participate in a mirrored volume, and all data is written to both volumes. As with all RAID configurations, use separate controllers (by adding a controller, you cre- ate a configuration called “duplexing”) for maximum performance. Mirrored volumes relate to RAID-1 hardware configurations. Create Mirrored Volumes To create a mirrored volume, you must have unallocated space on two dynamic disks. Right-click one of the spaces and choose Create Volume. The New Volume Wizard will step you through the process of selecting a mirrored volume and choosing space on another disk to include in the volume. Mirrored volumes can be assigned a drive letter and folder paths. Both copies of the mirror share the same assignment. You can also mirror an existing simple volume by right-clicking the volume and choos- ing Add Mirror and selecting a drive with sufficient unallocated space. Once you have established the mirror, the system begins copying data, sector by sec- tor. During that time, the volume status is reported as Resynching. Recovering from Mirrored Disk Failures The recovery process for a failed disk within a mirrored volume depends on the type of failure that occurs. If a disk has experienced transient I/O errors, both portions of Please purchase PDF Split-Merge on www.verypdf.com to remove this watermark. 11-36 Chapter 11 Managing Microsoft Windows Server 2003 Disk Storage the mirror will show a status of Failed Redundancy. The disk with the errors will report a status of Offline or Missing, as seen in Figure 11-8. Figure 11-8 A mirrored volume with a failed disk After correcting the cause of the I/O error—perhaps a bad cable connection or power supply—right-click the volume on the problematic disk and choose Reactivate Volume or right-click the disk and choose Reactivate Disk. Reactivating brings the disk or vol- ume back online. The mirror will then resynchronize automatically. If you want to stop mirroring, you have three choices, depending on what you want the outcome to be: ■ Delete the volume If you delete the volume, the volume and all the information it contains is removed. The resulting unallocated space is then available for new volumes. ■ Remove the mirror If you remove the mirror, the mirror is broken and the space on one of the disks becomes unallocated. The other disk maintains a copy of the data that had been mirrored, but that data is of course no longer fault-tolerant. ■ Break the mirror If you break the mirror, the mirror is broken but both disks maintain copies of the data. The portion of the mirror that you select when you choose Break Mirror maintains the original mirrored volume’s drive letter, shared folders, paging file, and reparse points. The secondary drive is given the next available drive letter. Knowing that information, how do you suppose you would replace a failed disk—a member of the mirrored volume that simply died? Well, after physically replacing the disk, you will need to open Disk Management to rescan, initialize the disk and convert it to dynamic. After all that work you will find that you can’t remirror a mirrored vol- ume, even though half of it doesn’t exist. So far as the remaining disk is concerned, the mirrored volume still exists—its partner in redundancy is just out to lunch. You must Please purchase PDF Split-Merge on www.verypdf.com to remove this watermark. ! Lesson 4 Implementing RAID 11 - 37 remove the mirror to break the mirror. Right-click the mirror and choose Remove Mir- ror. In the Remove Mirror dialog box, it is important to select the half of the volume that is missing; the volume you select will be deleted when you click Remove Mirror. The volume you did not select will become a simple volume. Once the operation is complete, right-click the healthy, simple volume and choose Add Mirror. Select the new disk and the mirror will be created again. Exam Tip Mirrored volumes provide fault tolerance and better write performance than RAID-5 volumes. However, because each disk in the mirror contains a full copy of the data in the volume, it is the least efficient type of volume in terms of disk utilization. RAID-5 Volumes A RAID-5 volume uses three or more physical disks to provide fault tolerance and excellent read performance while reducing the cost of fault tolerance in terms of disk capacity. Data is written to all but one disk in a RAID-5. That volume receives a chunk of data, called parity, which acts as a checksum and provides fault tolerance for the stripe. The calculation of parity during a write operation means that RAID-5 is quite intensive on the server’s processor for a volume that is not read-only. RAID-5 provides improved read performance, however, as data is retrieved from multiple spindles simultaneously. As data in a file is written to the volume, the parity is distributed among each disk in the set. But from a storage capacity perspective, the amount of space used for fault tol- erance is the equivalent of the space used by one disk in the volume. From a storage capacity perspective, that makes RAID-5 more economical than mirror- ing. In a minimal, three disk RAID-5 volume, one-third of the capacity is used for par- ity, as opposed to one-half of a mirrored volume being used for fault tolerance. Because as many as 32 disks can participate in a RAID-5 volume, you can theoretically configure a fault-tolerant volume which uses only 1/32 of its capacity to provide fault tolerance for the entire volume. Configure RAID-5 Volumes You need to have space on at least three dynamic disks to be able to create a RAID-5 volume. Right-click one disk’s unallocated space and choose New Volume. The New Volume Wizard will step you through selecting a RAID-5 volume type, and then select- ing the disks that will participate in the volume. The capacity of the volume is limited to the smallest section of unallocated space on any one of the volume’s disks. If Disk 2 has 50 GB of unallocated space, but Disks 3 and 4 have 100 GB of unallocated space, the stripe can only use 50 GB of space on Disks 3 and 4—the space used on each disk in the volume is identical. The capacity, Please purchase PDF Split-Merge on www.verypdf.com to remove this watermark. 11-38 Chapter 11 Managing Microsoft Windows Server 2003 Disk Storage or Volume Size reported by the New Volume Wizard will represent the amount of space available for data after accounting for parity. To continue our example, the RAID-5 volume size would be 100 GB—the total capacity minus the equivalent of one disk’s space for parity. RAID-5 volumes can be assigned a drive letter or folder paths. They can be formatted only with NTFS. Because RAID-5 volumes are created as native dynamic volumes from unallocated space, you cannot turn any other type of volume into a RAID-5 volume without back- ing up that volume’s data and restoring into the new RAID-5 volume. Recovering a Failed RAID-5 Volume If a single disk fails in a RAID-5 volume, data can continue to be accessed. During read operations, any missing data is regenerated on the fly through a calculation involving remaining data and parity information. Performance will be degraded and, of course, if a second drive fails it’s time to pull out the backup tapes. RAID-5 and mirrored vol- umes can only sustain a single drive failure. If the drive is returned to service, you may need to rescan, and then you will need to right-click the volume and choose Reactivate Volume. The system will then rebuild missing data and the volume will be fully functional again. If the drive does not offer a Reactivate option, or if you have had to replace the disk, you may need to rescan, initialize the disk, convert it to dynamic, then right-click the volume and choose Repair Volume. You will be asked to select the disk where the missing volume member should be recreated. Select the new disk and the system will regenerate the missing data. Mirrored Volumes versus RAID-5 Volumes Mirrored volumes (RAID-1) and RAID-5 volumes provide different levels of fault toler- ance. Deciding which option to implement depends on the level of protection you require and the cost of hardware. The major differences between mirrored volumes and RAID-5 volumes are performance and cost. Table 11-2 describes some differences between software-level RAID-1 and RAID-5. Table 11-2 RAID Performance and Costs Mirrored Volumes (RAID-1) Striped Volumes with Parity (RAID-5) Can protect system or boot parti- Cannot protect system or boot partition tion Requires two hard disks Requires a minimum of three hard disks and allows a max- imum of 32 hard disks Please purchase PDF Split-Merge on www.verypdf.com to remove this watermark. Lesson 4 Implementing RAID 11 - 39 Table 11-2 RAID Performance and Costs (Continued) Mirrored Volumes (RAID-1) Striped Volumes with Parity (RAID-5) Has a higher cost per MB Has a lower cost per MB 50 percent redundancy * 33 percent maximum redundancy * Has good read and write Has excellent read and moderate write performance performance Uses less system memory Requires more system memory * drive space dedicated or “lost” to provide fault tolerance Creating Fault Tolerance for the System Volume Because RAID-5 is a native dynamic volume, it is not possible to install or start the Windows Server 2003 operating system on a RAID-5 volume created by the Windows Server 2003 fault-tolerant disk technologies. Tip Hardware RAID, however, is invisible to Windows Server 2003, so the operating system can (and should, where available) be installed on hardware RAID arrays. The only option for creating fault tolerance for the system, without buying hardware RAID, is thus to mirror the system volume. You can mirror the system volume by fol- lowing the procedures described for creating a mirrored volume: right-click the system volume and choose Add Mirror. Unlike Windows 2000, you do not need to restart, and the BOOT.INI file is updated automatically so that you can start to the secondary drive if the primary drive fails. If the drives are attached to IDE controllers, and the primary drive fails, you may have to remove that drive, change the secondary drive to the primary controller and set its jumpers or cable position so that it is the master. Otherwise, the system may not boot to the secondary drive. Tip If you are going to mirror the system volume, do so on one or two SCSI controllers. If you use two controllers, make sure they are of the same type. This configuration will be the most easily supported and recovered. Please purchase PDF Split-Merge on www.verypdf.com to remove this watermark. 11-40 Chapter 11 Managing Microsoft Windows Server 2003 Disk Storage Upgrading Disks There are two potential “gotchas” when you upgrade disks from previous ver- sions of Windows, or attempt to move disks to a Windows Server 2003 computer from a computer running a previous version of Windows. First, if a disk was configured in a Windows 2000 computer as a basic disk, then was converted to dynamic, you cannot extend that disk’s simple volumes onto other disks using Windows Server 2003. In other words, if you move that disk to a Windows Server 2003 computer, or upgrade the operating system to Windows Server 2003, you cannot create spanned volumes out of the disk’s simple volumes. Second, Windows Server 2003 no longer supports multidisk arrays created in Windows NT 4. Windows NT 4 created mirrored, striped, and striped-with-parity (RAID-5) sets using basic disks. Windows 2000 permitted the use of those disk sets, although it was important to convert the sets to dynamic quickly in order to facilitate troubleshooting and recovery. Windows Server 2003 does not recognize the volumes. On the off chance that you upgrade a server from Windows NT 4 to Windows Server 2003, any RAID sets will no longer be visible. You must first back up all data prior to upgrading or moving those disks, and then, after recreating the fault-tolerant sets in Windows Server 2003, restore the data. Practice: Planning RAID Configuration In this practice, you will evaluate a server and its storage capacity against the require- ments of contoso.com and determine an appropriate configuration. You administer a server for Contoso, Ltd. The server has four disks on a SCSI subsystem: ■ Disk 0: 80 GB ■ Disk 1: 80 GB ■ Disk 2: 40 GB ■ Disk 3: 40 GB You recently performed a clean installation of Windows Server 2003 by backing up all data on the disks, removing all partitions from those disks, and installing the operating system on a 20 GB partition on Disk 0. You are now required to configure all the remaining drive space. User data will not be stored on the operating system volume. You want to maximize data storage and ensure uptime in the event of a single disk failure. What configuration do you implement, and what will the total storage capacity for user data be? Please purchase PDF Split-Merge on www.verypdf.com to remove this watermark. Lesson 4 Implementing RAID 11 - 41 The answer is a combination of RAID-5 and mirrored volumes with a total capacity for user data of 140 GB. To ensure uptime in the event of a single disk failure, you must provide fault tolerance for the operating system itself. Only a mirrored volume is capable of doing that; you cannot install or host the operating system on a RAID-5 volume. A minimum disk space of 20 GB is therefore required to mirror the operating system. A RAID-5 configuration maximizes disk space without sacrificing single disk failure fault tolerance. You can configure a RAID-5 volume with three or more disks. In this scenario, configuring a RAID-5 volume with all four disks would maximize data stor- age. A RAID-5 volume’s stripe can only be as wide as the smallest amount of unallo- cated space, so although disk 0 and 1 have 60 and 80 GB free, respectively, the smaller (40 GB) drives will determine the capacity of the volume. With a 40 GB space on four drives, the volume has a potential capacity of 160 GB, but RAID-5 uses the space equivalent to one disk for parity, meaning that the resulting capacity for data storage in this volume will be 120 GB. That leaves disk 0 with 20 GB of unallocated space, and disk 1 with 40 GB of unallo- cated space. You can configure the mirror of the operating system volume on disk 1, leaving 20 GB on that drive. The remaining space (20 GB per disk on disks 0 and 1) can be configured as a mirrored volume for user data, with a storage capacity of 20 GB. A simple, spanned, or striped volume would not be fault-tolerant, and a RAID-5 vol- ume requires a minimum of three physical disks, so a mirror is the most effective way to use remaining space for fault-tolerant data storage. Lesson Review The following questions are intended to reinforce key information presented in this lesson. If you are unable to answer a question, review the lesson materials and try the question again. You can find answers to the questions in the “Questions and Answers” section at the end of this chapter. 1. You’re implementing software RAID on your Windows Server 2003 computer. You want to provide fault tolerance to the system and boot partitions. Which version of RAID should you use? a. RAID-0 b. RAID-1 c. RAID-5 d. You cannot use software RAID to protect a boot partition. Please purchase PDF Split-Merge on www.verypdf.com to remove this watermark. 11-42 Chapter 11 Managing Microsoft Windows Server 2003 Disk Storage 2. You’re setting up a Windows Server 2003 computer and you want to protect the data on the hard disk. You want to implement a solution that provides the fastest disk I/O possible and supports the hot swapping of hard disks. Which RAID solu- tion should you use? a. RAID-0 b. RAID-1 c. RAID-5 d. Hardware RAID 3. You’re setting up RAID-5 on your Windows Server 2003 computer. You plan to use five hard disks, which are each 20 GB in size. What percentage of redundancy can you anticipate with this configuration? a. 20 b. 25 c. 33 d. 50 4. You’re setting up software RAID on your Windows Server 2003 computer to pro- vide fault tolerance to the data stored on that system. The computer is used as a database server. The server performs many read operations but relatively few write operations. As a result, you want a fault-tolerant solution that provides excel- lent read performance. Which RAID solution should you use? a. RAID-0 b. RAID-1 c. RAID-5 5. A computer where you want to implement RAID-5 contains three disks, each with 2 GB of unallocated space. Using the Disk Management snap-in, you start the New Volume Wizard by right-clicking one of the regions of unallocated space. When you reach the Select Volume Type screen, the RAID-5 option is not available. What is the most likely reason for this behavior? a. RAID-5 is already implemented in hardware. b. One or two of the disks are configured with the basic storage type. c. All three disks are configured with the dynamic storage type. d. All three disks are configured with the basic storage type. e. RAID-5 is already implemented in software. Please purchase PDF Split-Merge on www.verypdf.com to remove this watermark. Lesson 4 Implementing RAID 11 - 43 6. A disk in a mirrored volume is failing. You decide to replace the failing disk. How should you prepare the mirror for disk replacement? Lesson Summary ■ Some levels of RAID provide fault tolerance by implementing data redundancy. You can implement RAID fault tolerance as either a software or hardware solution. ■ Hardware solutions offer better performance than software solutions, but they are generally more expensive. ■ Windows Server 2003 supports three software implementations of RAID: striped volumes (RAID-0), mirrored volumes (RAID-1), and striped-with-parity volumes (RAID-5). ■ A striped volume (RAID-0) distributes data across each disk in the volume, provid- ing increased read and write performance, but no benefit to fault tolerance. ■ In a RAID-5 volume, fault tolerance is achieved by adding a parity-information stripe to each disk partition in the volume. ■ A mirrored volume uses the fault tolerance driver to write the same data to a vol- ume on each of two physical disks simultaneously. ■ The major differences between mirrored volumes and RAID-5 volumes are perfor- mance and cost. Mirrored volumes offer good read and write performance. RAID-5 volumes offer better read performance than mirrored volumes, but only moderate write performance. ■ The only form of software RAID that can be used for the system volume is a mir- rored volume. Case Scenario Exercise Note This case scenario requires Internet access. You are a server administrator for Contoso, Ltd. The company’s file servers are running out of disk capacity, and it is necessary to upgrade. In the past, the company has relied on tape backups for data redundancy. Due to recent growth, it is no longer acceptable to encounter more than a few minutes of downtime if a server disk drive fails. You have therefore been asked to evaluate disk storage options that provide fault tolerance. Please purchase PDF Split-Merge on www.verypdf.com to remove this watermark. 11-44 Chapter 11 Managing Microsoft Windows Server 2003 Disk Storage Exercise 1: Consider Windows Server 2003 Fault-Tolerant Volumes Review the information in Lesson 4 to consider how you could best configure fault- tolerant servers using Windows Server 2003 dynamic volumes. Use the Practice in Lesson 4 as a reminder of how various types of volumes can be configured to support fault tolerance. Consider the challenges related to IDE drives. If the operating system is installed on a mirrored IDE drive and the primary drive fails, you must reconfigure the secondary drive’s jumpers or cable position, and ensure it is attached to the primary IDE channel. With that in mind, you decide that a more robust configuration would utilize two SCSI controllers with one copy of the mirror as the first disk on each SCSI chain. That con- figuration would enable rapid recovery not only from a single drive failure, but from the failure of one of the SCSI controllers as well. Now consider the performance and capacity effect of Windows Server 2003 RAID. Consider the amount of time that will be required to recover if a drive fails—downing the server, replacing the drive, restarting the server—and the amount of time it will take to regenerate a missing volume. Exercise 2: Consider Hardware RAID With all those thoughts in mind, you decide to examine hardware RAID as an option. What advantages does hardware RAID provide? See Lesson 4 for some of the answers. Open Internet Explorer and browse to the Web site(s) of one or more computer hard- ware and supply vendors. Search their sites for RAID arrays. You will find RAID arrays, which include disk drives, and RAID controllers and RAID enclosures, to which you must add drives. Focus on the ready-to-go RAID arrays and answer the following questions: ■ What options are available? ■ What are some of the vendors of hardware RAID arrays? ■ What types of storage capacities do hardware RAID arrays offer? ■ What RAID configurations do the hardware RAID arrays implement? Are there configurations that Windows Server 2003 does not support? ■ What is the price range for a hardware RAID array? ■ What do some entry-level RAID arrays cost? Please purchase PDF Split-Merge on www.verypdf.com to remove this watermark. [...]... computer has Windows NT 4 installed on the first primary partition, and Windows Server 2003 installed on the second primary partition The computer is running low on disk space, so you add a new disk drive You boot to Windows Server 2003 and configure the drive as a dynamic disk When you later restart to Windows NT 4, you are unable to see the disk Why? Only Windows XP Windows 2000, and the Windows Server. .. emphasis on the role that the server fulfills and more on a consistent monitoring standard Server Roles Monitoring by server role is useful when servers perform within a single role in the network environment These roles are defined by the services or resources that the server provides to the users Examples of server roles include domain controllers, file servers, and Web servers A server s demand for resources... Microsoft Windows Server 2003 Before You Begin To follow and perform the practices in this chapter, you need: ■ A computer named Server0 1 with Windows Server 2003 installed ■ Server0 1 should be configured as a domain controller in the contoso.com domain Please purchase PDF Split-Merge on www.verypdf.com to remove this watermark Lesson 1 Using Event Viewer 12-3 Lesson 1: Using Event Viewer Windows Server. .. Monitoring Microsoft Windows Server 2003 File Replication Service This log contains errors or significant events reported by the File Replication Service related to the copying of information between Domain Controllers during a replication cycle Lastly, a Windows Server 2003 computer filling the role of a Domain Name System (DNS) server will contain one additional log: ■ DNS Server server This log contains... 20 minutes Logs Available in Event Viewer The Windows Server 2003 Event Log service, present and started automatically on all Windows Server 2003 computers, records events in one of three log files: ■ Application Developers of an application can program their software to report configuration changes, errors, or other events to this log ■ System The Windows Server 2003 operating system will report events... PDF Split-Merge on www.verypdf.com to remove this watermark 11-54 Chapter 11 Managing Microsoft Windows Server 2003 Disk Storage 4 You’re setting up software RAID on your Windows Server 2003 computer to provide fault tolerance to the data stored on that system The computer is used as a database server The server performs many read operations but relatively few write operations As a result, you want... www.verypdf.com to remove this watermark 11-46 Chapter 11 Managing Microsoft Windows Server 2003 Disk Storage When you return to the server room, you boot the servers Your server indicates errors, and you open Disk Management to see the following, frightening graphical view of your disks and volumes: Two drives have failed in the server One contained a mirror of the operating system volume The other contained... entries in the Security log reaches 512 KB? 3 You do not want data in the Security log to be overwritten, but also do not want your Windows Server 2003 computer to stop serving the network at any time What settings will you configure on your server? Lesson Summary The Windows Server 2003 Event Viewer contains several logs which report errors and significant events during system operation The System log... Counters The object counters that you choose in monitoring a server, either for a baseline or ongoing performance evaluation, can be considered in one of two ways One method of server monitoring examines the role that the server performs in the environment and the corresponding demands placed on that server by the user population Another view of server monitoring involves examining object categories of... 11 Managing Microsoft Windows Server 2003 Disk Storage 11-45 At the time of this writing, hardware RAID solutions offering 720 GB of storage—that’s closer to a terabyte than to the size of any single drive in most servers—can be pur­ chased for less than $3,000 How would you position the value of hardware RAID to your manager? Would you rec­ ommend hardware RAID over Windows Server 2003 RAID? Why or . disks using Windows Server 2003. In other words, if you move that disk to a Windows Server 2003 computer, or upgrade the operating system to Windows Server. and recovery. Windows Server 2003 does not recognize the volumes. On the off chance that you upgrade a server from Windows NT 4 to Windows Server 2003,