📄 asg11.htm
字号:
<HTML>
<HEAD>
<TITLE>Apache Server Survival Guide asg11.htm </TITLE>
<LINK REL="ToC" HREF="index.htm" tppabs="http://docs.rinet.ru:8080/Apachu/index.htm">
<LINK REL="Index" HREF="htindex.htm" tppabs="http://docs.rinet.ru:8080/Apachu/htindex.htm">
<LINK REL="Next" HREF="asg12.htm" tppabs="http://docs.rinet.ru:8080/Apachu/asg12.htm">
<LINK REL="Previous" HREF="asgpt4.htm" tppabs="http://docs.rinet.ru:8080/Apachu/asgpt4.htm"></HEAD>
<BODY BGCOLOR="#FFFFFF" TEXT="#000000" LINK="#0000FF" VLINK="#800080">
<!--#exec cmd="/www/docs/ssi-bin/restricted_search.ssi"-->
<!--#exec cmd="/www/docs/ssi-bin/inc.ssi"-->
<A NAME="I0"></A>
<H2>Apache Server Survival Guide asg11.htm</H2>
<P ALIGN=LEFT>
<A HREF="asgpt4.htm" tppabs="http://docs.rinet.ru:8080/Apachu/asgpt4.htm" TARGET="_self"><IMG SRC="purprev.gif" tppabs="http://docs.rinet.ru:8080/Apachu/purprev.gif" WIDTH = 32 HEIGHT = 32 BORDER = 0 ALT="Previous Page"></A>
<A HREF="index.htm" tppabs="http://docs.rinet.ru:8080/Apachu/index.htm" TARGET="_self"><IMG SRC="purtoc.gif" tppabs="http://docs.rinet.ru:8080/Apachu/purtoc.gif" WIDTH = 32 HEIGHT = 32 BORDER = 0 ALT="TOC"></A>
<A HREF="asg12.htm" tppabs="http://docs.rinet.ru:8080/Apachu/asg12.htm" TARGET="_self"><IMG SRC="purnext.gif" tppabs="http://docs.rinet.ru:8080/Apachu/purnext.gif" WIDTH = 32 HEIGHT = 32 BORDER = 0 ALT="Next Page"></A>
<HR ALIGN=CENTER>
<P>
<UL>
<UL>
<UL>
<LI>
<A HREF="#E68E138" >Making Backups</A>
<UL>
<LI>
<A HREF="#E69E127" >Backup Media</A>
<UL>
<LI>
<A HREF="#E70E123" >Floppy Disks</A>
<LI>
<A HREF="#E70E124" >Floptical Disks</A>
<LI>
<A HREF="#E70E125" >Magneto-Optical Disks</A>
<LI>
<A HREF="#E70E126" >Quarter-inch Cartridge Tapes (QIC)</A>
<LI>
<A HREF="#E70E127" >Travan Tapes</A>
<LI>
<A HREF="#E70E128" >Write-Once CD-ROMs</A>
<LI>
<A HREF="#E70E129" >Iomega Jaz and Zip drives</A>
<LI>
<A HREF="#E70E130" >Nine-Track Magnetic Tapes</A>
<LI>
<A HREF="#E70E131" >4mm DATs</A>
<LI>
<A HREF="#E70E132" >8mm Cartridge Tapes</A></UL>
<LI>
<A HREF="#E69E128" >A Backup Strategy</A>
<UL>
<LI>
<A HREF="#E70E133" >The dump Command</A>
<LI>
<A HREF="#E70E134" >restore</A></UL></UL>
<LI>
<A HREF="#E68E139" >Monitoring Disk Space</A>
<UL>
<LI>
<A HREF="#E69E129" >Rotating the Logs</A>
<LI>
<A HREF="#E69E130" >Resetting the Logs</A></UL>
<LI>
<A HREF="#E68E140" >Upgrading the Server</A>
<UL>
<LI>
<A HREF="#E69E131" >Keeping the Old Server Around</A></UL>
<LI>
<A HREF="#E68E141" >Making Sure It Is All Running</A>
<UL>
<LI>
<A HREF="#E69E132" >Monitoring Your Hosts and Network Interfaces</A>
<LI>
<A HREF="#E69E133" >Monitoring H TTP: httpd_Monitor and the Status Module</A>
<LI>
<A HREF="#E69E134" >Monitoring Your Name Server</A>
<UL>
<LI>
<A HREF="#E70E135" >Dealing with DNS Outages</A></UL></UL>
<LI>
<A HREF="#E68E142" >Summary</A></UL></UL></UL>
<HR ALIGN=CENTER>
<A NAME="E66E11"></A>
<H1 ALIGN=CENTER>
<CENTER>
<FONT SIZE=6 COLOR="#FF0000"><B>11</B></FONT></CENTER></H1>
<BR>
<A NAME="E67E16"></A>
<H2 ALIGN=CENTER>
<CENTER>
<FONT SIZE=6 COLOR="#FF0000"><B>Basic System Administration</B></FONT></CENTER></H2>
<BR>
<P>HTTP servers provide information; however, if your servers are unreachable, no one can get at this information. Your job as a system administrator is to ensure that your computers and networks are running smoothly. You must be both proactive and reactive. A proactive system administrator monitors his system resources to prevent basic problems, such as running out of disk space or some other disaster. A reactive system administrator has a contingency plan ready to be implemented in case of a disaster.
<BR>
<P>Proactive system administration is better than reactive system administration. Proactive administration can help you avoid the unpleasant experience of responding to a barrage of users' complaints about services that are down. However, should such a situation arise, your efficiency in resolving the matter (reactive administration) will affect how those complaining users perceive you and your level of competence. Therefore, it is your responsibility to maintain a close watch on all that is under your control.
<BR>
<P>The system administrator's central task is to orchestrate and choreograph the installation, setup, and maintenance of all hardware and software. Ancillary obligations can include setting up additional systems that help users obtain more information regarding access patterns and logs (HTTP logs and other UNIX logs).
<BR>
<P>The key word here is <I>maintenance</I>. This word can mean several different things: backing up your computers, pruning logfiles, and ensuring that name servers and HTTP servers are running. The most important of these is backing up your computers. If your system catastrophically failed, how long would it take you to get it up and running again? If it took you weeks to set up and install everything the first time, doing it over is not acceptable and definitely not fun. Instead, do it once and back it up. In case of a failure, replace the hardware or software that caused the failure with your backups.
<BR>
<P>If your information system is critical to your organization, any downtime is unacceptable. This means that you must build redundant systems that guarantee the trouble-free, continuous operation of your site. How much you can do depends on your budget.
<BR>
<BR>
<A NAME="E68E138"></A>
<H3 ALIGN=CENTER>
<CENTER>
<FONT SIZE=5 COLOR="#FF0000"><B>Making Backup</B><B>s</B></FONT></CENTER></H3>
<BR>
<P>Backing up is not hard to do, and if you want to keep your job as a system administrator, you should consider it an essential task. Although backing up is not difficult, it is tedious and time-consuming, especially when the disks you are backing up are large.
<BR>
<P>How can you back up a heavily used resource without taking it down and making it unavailable? How often should these backups occur? The answer to both of these questions is that <I>it depends</I>. A server that constantly has new information on it needs to be backed up more often than one that rarely changes. If your server is also a fileserver on which users or other programs store data, all bets are off. You don't have the luxury of determining what is a good interval; you will have to back it up daily.
<BR>
<P>Some technologies, such as Redundant Arrays of Inexpensive Disks (RAID), can provide automatic reliability, in case of media failure, and uninterrupted operation during hardware replacement. If a single drive on a RAID configuration fails, the data can be reconstructed from the information stored in the other drives and the redundant parity or Error Correcting Code (ECC) information. However, this feature will not help much if the root of the problem is a bad disk controller or some other problem that compromises the integrity of your data. RAID reliability is dependent on only a single drive going bad. RAID-6 arrays address this problem by allowing up to two disk failures without compromising the data. However, these multidimensional disk arrays have never been commercially implemented. Because of the auto-correcting nature of RAID, problems with the disk array are often found only when a second drive goes bad. By that time it's usually too late, and the likelihood of irreparable data loss is great. I suggest that you monitor your RAID array on a daily basis and back it up to ensure that you have a way to restore your files.
<BR>
<P>The good news is that Web servers don't change too often. If your machine is dedicated to just serving pages, your site will change when someone modifies it by adding, deleting, or updating information on the pages. The site also will change when you configure your server or install some new piece of software. How often you do backups depends on how much you are willing to lose. Keep in mind that your server logs may contain valuable information that takes time to accumulate, and unless you back them up, they will be lost. If your server also handles any sort of commercial transactions, you may want to make sure that the point-of-sale information is safely backed up.
<BR>
<P>How you handle your backup strategy is really a matter of personal preference. If you establish policies, such as describing what you back up, it becomes easier to do many system-administration tasks. Also, it is important to have the right hardware for making backups. By <I>right </I><I>hardware</I> I mean that the disks you back up must fit into a convenient backup medium; otherwise, you'll have more tapes than you'll know what to do with. If you can afford it, buy a tape drive. This medium is inexpensive and can hold a lot of data. Other backup solutions may work on your network, depending on how much data you need to back up.
<BR>
<BR>
<A NAME="E69E127"></A>
<H4 ALIGN=CENTER>
<CENTER>
<FONT SIZE=4 COLOR="#FF0000"><B>Backup Media</B></FONT></CENTER></H4>
<BR>
<P>There is an incredible array of choices for backup media these days:
<BR>
<UL>
<LI>Floppy disks
<BR>
<BR>
<LI>Floptical disks
<BR>
<BR>
<LI>Magneto-optical (MO) disks
<BR>
<BR>
<LI>Quarter-inch Cartridge tapes (QIC)
<BR>
<BR>
<LI>Travan tapes
<BR>
<BR>
<LI>Write-once CD-ROMs
<BR>
<BR>
<LI>Iomega Jaz and Zip drives
<BR>
<BR>
<LI>Nine-track magnetic tapes
<BR>
<BR>
<LI>4mm Digital Audio Tapes (DAT)
<BR>
<BR>
<LI>8mm cartridge tapes
<BR>
<BR>
</UL>
<BR>
<A NAME="E70E123"></A>
<H5 ALIGN=CENTER>
<CENTER>
<FONT SIZE=4 COLOR="#FF0000"><B>Floppy Disks</B></FONT></CENTER></H5>
<BR>
<P>Floppy disks are the most convenient backup medium available because your system likely has a built-in floppy disk drive. The standard capacity is 1.44MB. Some 2.88MB drives made it into the market a few years back, but they never caught on. The drawback of floppy disks is that they are slow, fairly expensive (about 50[155] to 60[155] per disk), and not very useful for backing up anything that is larger than a couple disks.
<BR>
<BR>
<A NAME="E70E124"></A>
<H5 ALIGN=CENTER>
<CENTER>
<FONT SIZE=4 COLOR="#FF0000"><B>Floptical Disks</B></FONT></CENTER></H5>
<BR>
<P>These higher-capacity disks take advantage of optical tracking technology to improve head positioning, and therefore maximize the amount of data that can be packed onto the surface of a disk. Floptical drives can read standard 1.44MB and 720KB floppy disks. Density of information can be anywhere from a few megabytes to 200MB per disk.
<BR>
<BR>
⌨️ 快捷键说明
复制代码
Ctrl + C
搜索代码
Ctrl + F
全屏模式
F11
切换主题
Ctrl + Shift + D
显示快捷键
?
增大字号
Ctrl + =
减小字号
Ctrl + -