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Amazon Elastic File System

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Re: Amazon Elastic File System

#121

Post by rectang »

click170 wrote: post #77
toomuchtodo wrote: post #69

Earlier quoted context omitted.

Depending on how you tune it, it can be a monster. Several years ago I was managing a cluster with ~5K linux instances all mounted to ~4PB of spinning disk served with NFS. Worked very well.

Can you speak to any stale NFS handle problems? I've used NFS at home and have had NFS file handle problems but IIRC that was only when there were problems like kernel faults or network partitions. However several of my colleagues at work have many NFS horror stories and are adamant that NFS does not scale well. Is NFS stability at scale simply a function of your underlying network and infrastructure stability in you…

Unlike typical local Unix file systems, NFS does not support "delete on last close" semantics.

Ordinarily, even if you unlink a file, the operating system keeps the inode around until the last filehandle referencing it goes away. But an NFS mount cannot know when all filehandles on all networked systems have closed. When you attempt to read from an NFS file handle whose underlying file has been deleted out from under you, BOOM -- `ESTALE`.

The solution is typically to guard against file deletion using read locks... which are extremely annoying to implement on NFS because of portability issues and cache coherency problems.

I'm not sure I'd describe that as a "scaling problem" per se, because it gets bad quickly and stays bad. It's more of a severe limitation on how applications and libraries can design their interaction with the file system.

Re: Amazon Elastic File System

#122

Post by chuckcode »

jeffbarr wrote: post #31
chuckcode wrote: post #16

I wish AWS would be a little more technical in their product descriptions and announcements. If there was ever an audience that wants technical data about how this type of technology will scale and compares to existing technology like glusterfs it would be the AWS users. Instead the performance specifications are ".. and is designed to provide the throughput, IOPS, and low latency needed for a broad range of workload…

We'll be providing a lot more details later.

I can understand that writing up technical details can be difficult as things are constantly improving and also as AWS has to be careful about what they claim. Perhaps a reasonable compromise would be to team up with some 3rd parties to let them try it, optimize a bit with techs from AWS and write up their experiences. Similar to how Apple does the marketing for the iPhone but then lets other people review it. Not perfect but perhaps something that would help the community understand and deploy these technologies better.

Re: Amazon Elastic File System

#124

Post by boynamedsue »

wmf wrote: post #108
alrs wrote: post #47

This is what should have existed instead of EBS all along. I'll never consider this to be as reliable as S3, but if I'm going to have a network filesystem I'd rather be dealing with NFS as my abstraction instead of virtualized network block devices.

AWS is lean so they build what's easy for them to build, not what should exist. You can gauge how hard a feature is by how long it took them to implement it.

They've been working on this for 2.5 years.

Re: Amazon Elastic File System

#125

Post by [deleted] »

chuckcode wrote: post #122
jeffbarr wrote: post #31

Earlier quoted context omitted.

We'll be providing a lot more details later.

I can understand that writing up technical details can be difficult as things are constantly improving and also as AWS has to be careful about what they claim. Perhaps a reasonable compromise would be to team up with some 3rd parties to let them try it, optimize a bit with techs from AWS and write up their experiences. Similar to how Apple does the marketing for the iPhone but then lets other people review it. Not pe…

[deleted]

Re: Amazon Elastic File System

#126

Post by efsavage »

vially wrote: post #94
rjurney wrote: post #82

Amazon is the only company other than Apple that consistently thought leads and innovates ahead of other companies and open source.

Would you mind explaining how exactly "Apple consistently leads and innovates ahead of other companies and open source"?

Maybe you didn't notice, but they just invented the Watch.

Imagine...if you could put a whole entire clock...on your wrist. Almost everybody has a wrist!

Re: Amazon Elastic File System

#127

Post by eknkc »

matheweis wrote: post #113
alexchamberlain wrote: post #50

Earlier quoted context omitted.

May I ask why? My experience with NFS is pretty bad performance wise.

Not sure why NFS gets such a bad rap. On a low-latency network, properly tuned NFS has very few, if any performance issues. I've personally seen read/write rates exceeding 800MByte/sec on more or less white-box hardware, at which point it was limited by the underlying storage infrastructure (8Gbit fiber), not the NFS protocols. Dell has a 2013 white paper (I'm not affiliated with them, fwiw) about their fairly white…

Is it really that good?

My only test case has been a VMWare virtual machine, mounting an nfs share from the host so I could work on my local filesystem and execute within the VM. Switched to a filesystem wather + rsync combo after struggling with poor random read performance. Maybe it was due to bad configuration but always thought it would be a poor choice for anything serius.

Re: Amazon Elastic File System

#128

Post by mrmondo »

jtchang wrote: post #36

Does anyone else cringe when someone suggestions using NFS in production? I can't be the only one that has been woken up at 2am because of an NFS outage.

I can't say I have any problems with NFS - we use it for shared storage on some pretty busy servers without any issue. I'm not saying they don't happen - just that we don't experience them. I'd be interested to hear the problems you've encountered - did you submit bug reports for them that you could perhaps link to?

Re: Amazon Elastic File System

#129

Post by rjurney »

vially wrote: post #94
rjurney wrote: post #82

Amazon is the only company other than Apple that consistently thought leads and innovates ahead of other companies and open source.

Would you mind explaining how exactly "Apple consistently leads and innovates ahead of other companies and open source"?

Are you kidding? Apple reinvents every space they enter with profound invention.

Do you remember computers before the Mac? Notebooks before the Macbook? Music players before the iPod? Phones before the iPhone? Tablets before the iPad? And in a month you'll think: watches before the Apple Watch?

Re: Amazon Elastic File System

#130

Post by simonw »

vizzah wrote: post #102
nkozyra wrote: post #42

Earlier quoted context omitted.

As has been mentioned, EBS can only be mounted to one instance at a time. If you could mount it to multiple it would effectively be the same thing, but then you have all sorts of write-locking issues. As the rest of the comments also allude, a lot of the cloud-entrenched world has abandoned NFS, or at least in AWS circles. I'm not one of these people. Rather than relying solely on puppet->all instances to handle mult…

Would it be a good idea to store Mysql db on EFS to be shared among load-balanced instances?

No, absolutely not. See the warning on http://dev.mysql.com/doc/refman/5.0/en/multiple-data-directo...
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