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<h1 class="topictitle1">Attaching an Existing Shared Disk</h1>
<div id="body1553256167534"><div class="section" id="evs_01_0076__section21771672164455"><h4 class="sectiontitle">Scenarios</h4><p id="evs_01_0076__p8113834171711">This section describes how to attach an existing shared disk to a server and use it as a data disk.</p>
<div class="p" id="evs_01_0076__p943216539478">You can view the disk information in the disk list. A shared disk can be attached to servers and used as a data disk when all of the following conditions are met:<ul id="evs_01_0076__ul112851310204915"><li id="evs_01_0076__li7285101004911">Disk Sharing: Enabled</li><li id="evs_01_0076__li628516108497">Function: Data disk</li><li id="evs_01_0076__li17285161084913">Status: In-use or Available</li></ul>
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<div class="section" id="evs_01_0076__section124341536184120"><h4 class="sectiontitle">Constraints</h4><div class="notice" id="evs_01_0076__evs_01_0037_note6425181162014"><span class="noticetitle"><img src="public_sys-resources/notice_3.0-en-us.png"> </span><div class="noticebody"><p id="evs_01_0076__evs_01_0037_p14254114202"><span id="evs_01_0076__evs_01_0037_ph174380122618">If you simply attach a shared disk to multiple <span id="evs_01_0076__evs_01_0037_evs_faq_0039_text382154512348">server</span>s, files cannot be shared among them. Because there are no mutually agreed data read/write rules among <span id="evs_01_0076__evs_01_0037_evs_faq_0039_text61093113231">server</span>s, read and write operations from them may interfere with each other, or unpredictable errors may occur.</span> To share files between <span id="evs_01_0076__evs_01_0037_text44381821083">servers</span>, set up a shared file system or a clustered management system first.</p>
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<ul id="evs_01_0076__evs_01_0037_ul3314195354412"><li id="evs_01_0076__evs_01_0037_li6314125304417">A shared disk can be attached to a maximum of 16 <span id="evs_01_0076__evs_01_0037_text18175184004110">servers</span>. These <span id="evs_01_0076__evs_01_0037_text6234359121018">server</span>s and the shared disk must be in the same AZ within a region.</li><li id="evs_01_0076__evs_01_0037_li399917404445">A shared, <strong id="evs_01_0076__evs_01_0037_b7601152172120">In-use</strong> disk can be attached to other <span id="evs_01_0076__evs_01_0037_text1332182051312">server</span>s only when the maximum number of <span id="evs_01_0076__evs_01_0037_text1120131723418">server</span>s that the disk can be attached to has not been reached.</li><li id="evs_01_0076__evs_01_0037_li17802167204516">All the <span id="evs_01_0076__evs_01_0037_text2091725624317">servers</span> attached with a shared disk must run either Windows or Linux.<p id="evs_01_0076__evs_01_0037_p1959710189136">For example, if you attach a shared disk to multiple Windows <span id="evs_01_0076__evs_01_0037_text6638115184110">servers</span> and then detach it from these <span id="evs_01_0076__evs_01_0037_text107021469311">servers</span>, the shared disk cannot be attached to Linux <span id="evs_01_0076__evs_01_0037_text7430155574111">servers</span> later. This is because Windows and Linux support different file systems and cannot identify the original file system on the disk. Improper operations may damage the original file system.</p>
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<ul id="evs_01_0076__evs_01_0037_ul1565516417459"><li id="evs_01_0076__evs_01_0037_li1265524124514">A shared disk can only be used as a data disk. It cannot be used as a system disk.</li><li id="evs_01_0076__evs_01_0037_li35413524595"><span id="evs_01_0076__evs_01_0037_ph37501425112">Cloud servers created from ISO images are only used for OS installation. They have limited functions and cannot have EVS disks attached.</span></li><li id="evs_01_0076__evs_01_0037_li58589237329">A shared disk can be attached only when the <span id="evs_01_0076__evs_01_0037_ph1228512571014"><span id="evs_01_0076__evs_01_0037_text182859519103">servers</span></span>' statuses are <strong id="evs_01_0076__evs_01_0037_b16419102751420">Running</strong> or <strong id="evs_01_0076__evs_01_0037_b105951630121412">Stopped</strong>.</li><li id="evs_01_0076__evs_01_0037_li13985152101111">A frozen disk cannot be attached.</li></ul>
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<div class="section" id="evs_01_0076__section198622019467"><h4 class="sectiontitle">Procedure</h4><ol id="evs_01_0076__ol1977955163311"><li id="evs_01_0076__li3864162312418"><span>Log in to the management console.</span></li><li id="evs_01_0076__li153618295518"><span>Click <span><img id="evs_01_0076__en-us_topic_0021738346_image052111582392" src="en-us_image_0237893718.png"></span> in the upper left corner and select the desired region and project.</span></li><li id="evs_01_0076__li3843952015053"><span>Under <strong id="evs_01_0076__b1549119128917">Storage</strong>, click <strong id="evs_01_0076__b15491131214911">Elastic Volume Service</strong>.</span><p><p id="evs_01_0076__p16002076152423">The disk list page is displayed.</p>
</p></li><li id="evs_01_0076__li28321507201951"><span>Locate the target disk in the list and click <strong id="evs_01_0076__b95886141398">Attach</strong>.</span><p><ul id="evs_01_0076__ul42551702019"><li id="evs_01_0076__li22551102011">Shared disks support batch attachment so that you can attach a shared disk to multiple <span id="evs_01_0076__text6057743320429">servers</span>. The left area in the <strong id="evs_01_0076__b205603720211347">Attach Disk</strong> dialog box shows the <span id="evs_01_0076__text1968660444114236">server</span> list. After you select the target <span id="evs_01_0076__text869171055114243">servers</span>, the selected <span id="evs_01_0076__text14382275114250">servers</span> will be displayed in the right area.</li><li id="evs_01_0076__li4256702008">A shared disk can be attached to servers only when the disk status is <strong id="evs_01_0076__b2451153101015">Available</strong> or <strong id="evs_01_0076__b85119565101">In-use</strong>.</li></ul>
</p></li><li id="evs_01_0076__li99951459113919"><span>Select the target <span id="evs_01_0076__evs_01_0037_text119701013917">servers</span> you want to attach the shared disk. Ensure that the disk and servers are in the same AZ. After you select <span id="evs_01_0076__evs_01_0037_text286215918343">the server</span>s, <strong id="evs_01_0076__evs_01_0037_b16200501122">Data disk</strong> is automatically entered as the disk function for each server.</span><p><p id="evs_01_0076__evs_01_0037_p15286616814"></p>
</p></li><li id="evs_01_0076__li16131059163716"><span id="evs_01_0076__evs_01_0037_p16410192715301">Click <span class="uicontrol" id="evs_01_0076__evs_01_0037_uicontrol1941011279308"><b>OK</b></span> to return to the disk list page.</span><p><p id="evs_01_0076__evs_01_0037_li2439421982p0">The status of the disk is <strong id="evs_01_0076__evs_01_0037_b463819278283">Attaching</strong>, indicating that the disk is being attached to the servers. When the disk status changes to <strong id="evs_01_0076__evs_01_0037_b76181948122813">In-use</strong>, the disk is successfully attached.</p>
</p></li><li id="evs_01_0076__li16115125145214"><span>(Optional) Mount the existing disk partition to a mount point if you have attached the disk to a Linux server. The mount command is as follows:</span><p><pre class="screen" id="evs_01_0076__evs_01_0075_screen17484192434911"><strong id="evs_01_0076__evs_01_0075_b4366111819528">mount</strong> <em id="evs_01_0076__evs_01_0075_i5367121814520">Disk partition</em> <em id="evs_01_0076__evs_01_0075_i1367171813522">Mount point</em></pre>
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<div class="section" id="evs_01_0076__section599211611227"><h4 class="sectiontitle">Related Operations</h4><p id="evs_01_0076__evs_01_0074_p6201105315200">For more attachment FAQs, see <a href="evs_01_0078.html">Attachment</a>.</p>
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<div class="parentlink"><strong>Parent topic:</strong> <a href="evs_01_0073.html">Attaching an Existing Disk</a></div>
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