{"id":24,"date":"2008-10-03T04:57:23","date_gmt":"2008-10-03T08:57:23","guid":{"rendered":"http:\/\/interscapetech.com\/blog\/?page_id=24"},"modified":"2012-12-07T03:06:28","modified_gmt":"2012-12-07T07:06:28","slug":"definitions","status":"publish","type":"page","link":"https:\/\/www.interscape.io\/blog\/definitions","title":{"rendered":"Definitions"},"content":{"rendered":"

SAN ( Storage Area Network )<\/strong><\/h2>\n

In\u00a0information technology<\/a>, a\u00a0storage area network<\/strong> (SAN<\/strong>) is an architecture to attach remote computer storage devices (such as\u00a0disk arrays<\/a>,\u00a0tape libraries<\/a> and\u00a0optical jukeboxes<\/a>) to\u00a0servers<\/a> in such a way that, to the\u00a0operating system<\/a>, the devices appear as\u00a0locally attached<\/a>. Although cost and complexity are dropping, as of 2007, SANs are still uncommon outside larger\u00a0enterprises<\/a>.<\/p>\n

NAS ( <\/strong>Network Attached Storage<\/a> )<\/strong><\/p>\n

In contrast to a SAN,\u00a0Network Attached Storage<\/a> (NAS) uses file-based protocols such as\u00a0NFS<\/a> or\u00a0SMB\/CIFS<\/a> where it is clear that the storage is remote, and computers request a portion of an abstract file rather than a disk block.<\/p>\n

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NAS network schema<\/p>\n

Clustered NAS<\/strong><\/p>\n

A\u00a0clustered NAS<\/strong> is a\u00a0Network-attached storage<\/a> solution which is using a distributed file system running simultaneously on multiple\u00a0servers<\/a>. The key differentiating factor of clustered NAS from traditional NAS is its ability to stripe data and metadata across the cluster nodes and storage subsystems, and provide access to the networked file system from any of the cluster nodes, unrelated to the actual location of the data. For this reason clustered NAS solutions are typically associated with virtualization.<\/p>\n

VMSTAT\u00a0( virtual memory statistics )<\/strong><\/p>\n

vmstat<\/strong> (virtual memory statistics) is a computer\u00a0operating system<\/a> monitoring tool that collects and displays summary information about memory, processes, interrupts, paging and block\u00a0I\/O<\/a>information. By specifying the interval, it can be used to observe system activity interactively.<\/p>\n

The vmstat tool is available on most\u00a0UNIX<\/a> and\u00a0Unix-like<\/a> operating systems, such as\u00a0Linux<\/a>. The syntax and output of vmstat often differs slightly between different operating systems.<\/p>\n

Example:<\/strong><\/p>\n

#> vmstat 2 6\r\nprocs -----------memory---------- ---swap-- -----io---- --system-- ----cpu----\r\n r  b   swpd   free   buff  cache   si   so    bi    bo   in    cs us sy id wa\r\n 0  0   2536  21496 185684 1353000    0    0     0    14    1     2  0  0 100  0\r\n 0  0   2536  21496 185684 1353000    0    0     0    28 1030   145  0  0 100  0\r\n 0  0   2536  21496 185684 1353000    0    0     0     0 1026   132  0  0 100  0\r\n 0  0   2536  21520 185684 1353000    0    0     0     0 1033   186  1  0 99  0\r\n 0  0   2536  21520 185684 1353000    0    0     0     0 1024   141  0  0 100  0\r\n 0  0   2536  21584 185684 1353000    0    0     0     0 1025   131  0  0 100  0\r\n#><\/pre>\n

\n<\/span><\/div>\n<\/div>\n<\/div>\n<\/div>\n","protected":false},"excerpt":{"rendered":"
SAN ( Storage Area Network ) In\u00a0information technology, a\u00a0storage area network (SAN) is an architecture to attach remote computer storage devices (such as\u00a0disk arrays,\u00a0tape libraries and\u00a0optical jukeboxes) to\u00a0servers in such a way that, to the\u00a0operating system, the devices appear as\u00a0locally attached. Although cost and complexity are dropping, as of 2007, SANs are still uncommon outside\u2026 Read More »<\/a><\/span><\/p>\n","protected":false},"author":36,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-24","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.interscape.io\/blog\/wp-json\/wp\/v2\/pages\/24","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.interscape.io\/blog\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/www.interscape.io\/blog\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/www.interscape.io\/blog\/wp-json\/wp\/v2\/users\/36"}],"replies":[{"embeddable":true,"href":"https:\/\/www.interscape.io\/blog\/wp-json\/wp\/v2\/comments?post=24"}],"version-history":[{"count":11,"href":"https:\/\/www.interscape.io\/blog\/wp-json\/wp\/v2\/pages\/24\/revisions"}],"predecessor-version":[{"id":248,"href":"https:\/\/www.interscape.io\/blog\/wp-json\/wp\/v2\/pages\/24\/revisions\/248"}],"wp:attachment":[{"href":"https:\/\/www.interscape.io\/blog\/wp-json\/wp\/v2\/media?parent=24"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}