Re: [CentOS] CentOS Digest, Vol 60, Issue 13
Another issue to consider with SSDs is that they are based on Flash technology. Each flash cell can only be written on about 10,000 to 100,000 times or so (*), so if you're using extensive read/write on your server you will be impacted. SSD manufacturers go around this issue by giving some intelligence to the drive controllers, so that they minimize the per-cell usage (which means moving things around a bit internally, transparently to you), so in many cases you will not see any impact. However, I would be careful on what I run on it, and what services are enabled, maybe having another disk around for write intensive apps. Emanuel (*) http://en.wikipedia.org/wiki/Solid-state_drive#Disadvantages Emanuel Machado, PhD. Senior Engineer, Project Leader Cytonome/ST, LLC. 27 Drydock Ave Boston, MA 02210 Voice: (617) 330-5030 ext. 237 Fax: (617) 330-5031 Website: www.cytonomest.com Email: emach...@cytonomest.com Please consider the environment before printing this email. -Original Message- From: centos-boun...@centos.org [mailto:centos-boun...@centos.org] On Behalf Of centos-requ...@centos.org Sent: Wednesday, January 13, 2010 12:00 PM To: centos@centos.org Subject: CentOS Digest, Vol 60, Issue 13 Send CentOS mailing list submissions to centos@centos.org To subscribe or unsubscribe via the World Wide Web, visit http://lists.centos.org/mailman/listinfo/centos or, via email, send a message with subject or body 'help' to centos-requ...@centos.org You can reach the person managing the list at centos-ow...@centos.org When replying, please edit your Subject line so it is more specific than Re: Contents of CentOS digest... ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] CentOS Digest, Vol 60, Issue 13
Emanuel Machado wrote: Another issue to consider with SSDs is that they are based on Flash technology. Each flash cell can only be written on about 10,000 to 100,000 times or so (*), so if you're using extensive read/write on your server you will be impacted. SSD manufacturers go around this issue by giving some intelligence to the drive controllers, so that they minimize the per-cell usage (which means moving things around a bit internally, transparently to you), so in many cases you will not see any impact. However, I would be careful on what I run on it, and what services are enabled, maybe having another disk around for write intensive apps. No, you can write (append) as often as you like. It is the erase cycles that are limited. So the chip life depends on how often those files get deleted. Bob McConnell N2SPP ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] CentOS Digest, Vol 60, Issue 13
On 1/13/2010 3:31 PM, Bob McConnell wrote: Emanuel Machado wrote: Another issue to consider with SSDs is that they are based on Flash technology. Each flash cell can only be written on about 10,000 to 100,000 times or so (*), so if you're using extensive read/write on your server you will be impacted. SSD manufacturers go around this issue by giving some intelligence to the drive controllers, so that they minimize the per-cell usage (which means moving things around a bit internally, transparently to you), so in many cases you will not see any impact. However, I would be careful on what I run on it, and what services are enabled, maybe having another disk around for write intensive apps. No, you can write (append) as often as you like. It is the erase cycles that are limited. So the chip life depends on how often those files get deleted. But every time you append to a file the inode info is updated and the free space list may need to be rewritten so it dies when erase/write count is exceeded on the filesystem metadata. If you don't turn off atime updates, you'll rewrite even on file reads. -- Les Mikesell lesmikes...@gmail.com ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
