Comments on: NFS vs iSCSI http://rajeev.name/2005/10/12/nfs-vs-iscsi/ technologist defying the peter principle Fri, 09 Mar 2012 17:19:54 +0000 hourly 1 http://wordpress.org/?v=3.3.1 By: Madhu M http://rajeev.name/2005/10/12/nfs-vs-iscsi/comment-page-1/#comment-29575 Madhu M Thu, 13 May 2010 15:05:17 +0000 http://rajeev.name/2005/10/12/nfs-vs-iscsi/#comment-29575 Hi Rajeev, Very impressive graphs. We are setting up a lab for virtualization ( we are a startup right now) and we want to have shared storage for vmotion/xenmotion etc. We definitely can't afford a SAN hence looking at ISCSI and NFS. Can you tell me what would be a better option and which is cheaper ? I think performance wise,iscsi is better but costlier than NFS. Can you point me in the right direction ? thanks Madhu M Hi Rajeev,

Very impressive graphs. We are setting up a lab for virtualization ( we are a startup right now) and we want to have shared storage for vmotion/xenmotion etc. We definitely can’t afford a SAN hence looking at ISCSI and NFS. Can you tell me what would be a better option and which is cheaper ? I think performance wise,iscsi is better but costlier than NFS. Can you point me in the right direction ?

thanks

Madhu M

]]> By: rajeev karamchedu http://rajeev.name/2005/10/12/nfs-vs-iscsi/comment-page-1/#comment-30 rajeev karamchedu Mon, 06 Mar 2006 02:15:06 +0000 http://rajeev.name/2005/10/12/nfs-vs-iscsi/#comment-30 More memory on the NFS clients, some tweaking to the NFS options (actimeo) helped us cut down the overhead calls. Our environment is also very symlink greedy which contributes to the unusually high number of GETATTR calls. Even after the attrs are cached on the client, GETATTRs are issued to revalidate that information. With regards to the graphs - your guess is right. They are made using RRD tool. You may want to look at <a href="http://web.taranis.org/drraw/" rel="nofollow">drraw</a> for help with graphs. More memory on the NFS clients, some tweaking to the NFS options (actimeo) helped us cut down the overhead calls. Our environment is also very symlink greedy which contributes to the unusually high number of GETATTR calls. Even after the attrs are cached on the client, GETATTRs are issued to revalidate that information.

With regards to the graphs – your guess is right. They are made using RRD tool. You may want to look at drraw for help with graphs.

]]> By: Blake Golliher http://rajeev.name/2005/10/12/nfs-vs-iscsi/comment-page-1/#comment-26 Blake Golliher Wed, 22 Feb 2006 05:04:29 +0000 http://rajeev.name/2005/10/12/nfs-vs-iscsi/#comment-26 In most cases I've seen, nfs will be faster then unaccerlated iSCSI, that is to say iscsi without the benefit of a hardware initiator. The Linux and Solaris NFS client has been tuned for a long time to be a pretty efficent data moving machine, so your tests may suprise you. In this case, you have a pretty good amount of lookup and access calls, which are harder on NFS then their local FS equivalent. But they are still overhead, you may benefit from a directory structure rehash, if you can afford it. It may help you cut down on LOOKUP calls. If you increase the attribute cache, it may cut down your ACCESS calls. You seem to have a low amount of WRITE so a longer cache of attributes should be safe. My question, is how did you make these wonderful graphs!? I always endup with some ugly awk hack that pipes to a CSV file which I then make a graph in excel with. RRD is much prettier. -Blake In most cases I’ve seen, nfs will be faster then unaccerlated iSCSI, that is to say iscsi without the benefit of a hardware initiator. The Linux and Solaris NFS client has been tuned for a long time to be a pretty efficent data moving machine, so your tests may suprise you.

In this case, you have a pretty good amount of lookup and access calls, which are harder on NFS then their local FS equivalent. But they are still overhead, you may benefit from a directory structure rehash, if you can afford it. It may help you cut down on LOOKUP calls. If you increase the attribute cache, it may cut down your ACCESS calls. You seem to have a low amount of WRITE so a longer cache of attributes should be safe.

My question, is how did you make these wonderful graphs!? I always endup with some ugly awk hack that pipes to a CSV file which I then make a graph in excel with. RRD is much prettier.

-Blake

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