mongodb 持久化(3)-Mysql Tutorial-php.cn

mongodb 持久化(3)

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Release： 2016-06-07 16:36:01

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1. 载体崩溃当出现硬件问题或文件系统出错，特别是硬盘损坏了，就没法保护数据安全了。另外，不同品牌的硬件和软件具有不同的持久保证的。总而言之，如果硬件或文件系统破坏了数据，MongoDB是无法保护数据的，这已经属于底层存储的事情了。可以使用复制来避

1. 载体崩溃

当出现硬件问题或文件系统出错，特别是硬盘损坏了，就没法保护数据安全了。另外，不同品牌的硬件和软件具有不同的持久保证的。总而言之，如果硬件或文件系统破坏了数据，MongoDB是无法保护数据的，这已经属于底层存储的事情了。可以使用复制来避免这个问题，其实就是单点问题了。

2. ?检查损坏

validate命令用来检测一个集合的损坏，如：

> db.posts.validate({full:true})
{
        "ns" : "ttlsa_com.posts",
        "firstExtent" : "1:1036000 ns:ttlsa_com.posts",
        "lastExtent" : "4:2000 ns:ttlsa_com.posts",
        "extentCount" : 14,
        "extents" : [
                {
                        "loc" : "1:1036000",
                        "xnext" : "1:104e000",
                        "xprev" : "null",
                        "nsdiag" : "ttlsa_com.posts",
                        "size" : 61440,
                        "firstRecord" : "1:1037c30",
                        "lastRecord" : "1:103e4f0"
                },
                {
                        "loc" : "1:104e000",
                        "xnext" : "1:108a000",
                        "xprev" : "1:1036000",
                        "nsdiag" : "ttlsa_com.posts",
                        "size" : 245760,
                        "firstRecord" : "1:104e0b0",
                        "lastRecord" : "1:10556b0"
                },
                {
                        "loc" : "1:108a000",
                        "xnext" : "1:117a000",
                        "xprev" : "1:104e000",
                        "nsdiag" : "ttlsa_com.posts",
                        "size" : 983040,
                        "firstRecord" : "1:108a0b0",
                        "lastRecord" : "1:109a9b0"
                },
                {
                        "loc" : "1:117a000",
                        "xnext" : "1:155e000",
                        "xprev" : "1:108a000",
                        "nsdiag" : "ttlsa_com.posts",
                        "size" : 3932160,
                        "firstRecord" : "1:117a0b0",
                        "lastRecord" : "1:13739f0"
                },
                {
                        "loc" : "1:155e000",
                        "xnext" : "1:24ee000",
                        "xprev" : "1:117a000",
                        "nsdiag" : "ttlsa_com.posts",
                        "size" : 15728640,
                        "firstRecord" : "1:155e0b0",
                        "lastRecord" : "1:1bbe4f0"
                },
                {
                        "loc" : "1:24ee000",
                        "xnext" : "1:392e000",
                        "xprev" : "1:155e000",
                        "nsdiag" : "ttlsa_com.posts",
                        "size" : 21233664,
                        "firstRecord" : "1:24ee8b0",
                        "lastRecord" : "1:2b485b0"
                },
                {
                        "loc" : "1:392e000",
                        "xnext" : "1:56c5000",
                        "xprev" : "1:24ee000",
                        "nsdiag" : "ttlsa_com.posts",
                        "size" : 28667904,
                        "firstRecord" : "1:392e0b0",
                        "lastRecord" : "1:450dd30"
                },
                {
                        "loc" : "1:56c5000",
                        "xnext" : "2:2000",
                        "xprev" : "1:392e000",
                        "nsdiag" : "ttlsa_com.posts",
                        "size" : 38703104,
                        "firstRecord" : "1:56c50b0",
                        "lastRecord" : "1:617c0b0"
                },
                {
                        "loc" : "2:2000",
                        "xnext" : "2:3ad7000",
                        "xprev" : "1:56c5000",
                        "nsdiag" : "ttlsa_com.posts",
                        "size" : 52252672,
                        "firstRecord" : "2:20b0",
                        "lastRecord" : "2:188ac30"
                },
                {
                        "loc" : "2:3ad7000",
                        "xnext" : "2:7e1d000",
                        "xprev" : "2:2000",
                        "nsdiag" : "ttlsa_com.posts",
                        "size" : 70541312,
                        "firstRecord" : "2:3ad7470",
                        "lastRecord" : "2:66b8af0"
                },
                {
                        "loc" : "2:7e1d000",
                        "xnext" : "3:2000",
                        "xprev" : "2:3ad7000",
                        "nsdiag" : "ttlsa_com.posts",
                        "size" : 95232000,
                        "firstRecord" : "2:7e1d0b0",
                        "lastRecord" : "2:be8a2b0"
                },
                {
                        "loc" : "3:2000",
                        "xnext" : "3:dd21000",
                        "xprev" : "2:7e1d000",
                        "nsdiag" : "ttlsa_com.posts",
                        "size" : 128565248,
                        "firstRecord" : "3:20b0",
                        "lastRecord" : "3:63eb670"
                },
                {
                        "loc" : "3:dd21000",
                        "xnext" : "4:2000",
                        "xprev" : "3:2000",
                        "nsdiag" : "ttlsa_com.posts",
                        "size" : 173563904,
                        "firstRecord" : "3:dd210b0",
                        "lastRecord" : "3:12fccc30"
                },
                {
                        "loc" : "4:2000",
                        "xnext" : "null",
                        "xprev" : "3:dd21000",
                        "nsdiag" : "ttlsa_com.posts",
                        "size" : 234311680,
                        "firstRecord" : "4:20b0",
                        "lastRecord" : "4:7bec3b0"
                }
        ],
        "datasize" : 614217440,
        "nrecords" : 305603,
        "lastExtentSize" : 234311680,
        "padding" : 1.0000000000221079,
        "firstExtentDetails" : {
                "loc" : "1:1036000",
                "xnext" : "1:104e000",
                "xprev" : "null",
                "nsdiag" : "ttlsa_com.posts",
                "size" : 61440,
                "firstRecord" : "1:1037c30",
                "lastRecord" : "1:103e4f0"
        },
        "lastExtentDetails" : {
                "loc" : "4:2000",
                "xnext" : "null",
                "xprev" : "3:dd21000",
                "nsdiag" : "ttlsa_com.posts",
                "size" : 234311680,
                "firstRecord" : "4:20b0",
                "lastRecord" : "4:7bec3b0"
        },
        "objectsFound" : 305603,
        "invalidObjects" : 0,
        "bytesWithHeaders" : 619107088,
        "bytesWithoutHeaders" : 614217440,
        "deletedCount" : 125358,
        "deletedSize" : 244912976,
        "nIndexes" : 9,
        "keysPerIndex" : {
                "ttlsa_com.posts.$_id_" : 305603,
                "ttlsa_com.posts.$index_doctorSn" : 305603,
                "ttlsa_com.posts.$index_doctorUid" : 305603,
                "ttlsa_com.posts.$index_hosDeptId" : 305603,
                "ttlsa_com.posts.$index_hospitalId" : 305603,
                "ttlsa_com.posts.$doctorNumberList_1_doctorOrderId_-1" : 305924,
                "ttlsa_com.posts.$cityId_1_displayStatus_1" : 305603,
                "ttlsa_com.posts.$standardDeptId_1_displayStatus_1" : 305603,
                "ttlsa_com.posts.$doctorCode_1" : 305603
        },
        "valid" : true,
        "errors" : [ ],
        "ok" : 1
}

Copy after login

在上面输出底部，有个"valid" : true 说明没有损坏，如果不是，会找到一些损坏的细节。大部分输出是描述集合内部的结构，对于调试不是特别有用的。只能检测集合，不能检测索引。如果出现无效的BSONbj，通常就是损坏了。最糟糕的是出现pdfile，pdfile基本上是mongodb的数据存储核心，几乎可以判断数据文件已经损坏了。如果出现损坏，会看到下面的日志信息： Tue Dec 20 01:12:09 [initandlisten] Assertion: 10334: Invalid BSONObj size: 285213831 (0x87040011) first element: _id: ObjectId('4e5efa454b4ae20fa6000013') 如果第一个元素显示的是垃圾，不需要做什么。如果第一个元素是可见的，可以移除损坏的文档。如： > db.remove({_id: ObjectId('4e5efa454b4ae20fa6000013')}) 如果损坏并不局限于该文档，这种技术可能无法工作，你仍然需要进行修复。