Interesting We run a fair few filers in the 97%-99% arena, mainly as CIFS NAS devices. Every time I've seen it hit 100% 0 bytes available CIFS has refused to save anything.
I've definitely seen he performance hit of adding too few disks at the same time...my usual trick is to add in half or full raidgroups and do it on a weekend so theres a chance for weekend users to fill up some disk. If I need to use less disks I usually do it on a Sat morning and run wafl scan reallocate to respread the data over the weekend...thats usually a big hit to snapshot space for us and in recent versions of Ontap, reallocate will hang if there isn't about 10% free snapshot and 10% free disk
-----Original Message----- From: owner-toasters@mathworks.com [mailto:owner-toasters@mathworks.com] On Behalf Of Blake Golliher Sent: Thursday, 23 February 2006 4:26 PM To: jburto1@yahoo.com Cc: toasters@mathworks.com Subject: Re: maxing out the filesystem
A filer can be written to over 100% space utilization, it'll just keep growing. I've seen filers go up tot 107% space utilization before. On a full volume, what you'll see suffer are writes, as the filer has to work harder to find free contiguous space to write a stripe to. You may see read problems, but only if you have high churn.
It sounds like you aren't all that performance centric, however. I'd say keep it in the 90% range. When you get the chance get some disks. I'd recommend you add disks in sets of raidgroups. If you have a 10 disk raid group, add another 10 (watch the vol option raidsize setting!). Do not add one disk at a time, since your setting yourself up for failure. All your new writes will go to the new disks, and so all reads will as well.
-Blake
On 2/22/06, Jeff Burton jburto1@yahoo.com wrote:
We have a FAS940C that has 2 trad volumes (5TB & 3TB, 144GB/FC drives) that are always around 95%+ full because of funding and timing issues. Only when we run out of space do we start deleting snapshots, otherwise there are always a few hundred GB of snapshots. We've been running over 90% for the past year and have never had an outage or major hiccup...just a few disk failures. We typically have 4k-5k active CIFS connections and around 100 NFS connections. Clients have never noticed a performance problem, and our CPU utilization hovers between 30% and 50%. So maybe we do not notice a problem because there is more than enough CPU cycles left over for DOT/WAFL to deal with the full file system.
Jeff
--- Glenn Dekhayser gdekhayser@voyantinc.com wrote:
Netapp recommends that you keep the fileysystems at 80% or less. Otherwise, WAFL starts to work very hard finding places to put data, and you'll see CPU spikes, High disk utilization, and degraded performance.
Glenn
-----Original Message----- From: owner-toasters@mathworks.com [mailto:owner-toasters@mathworks.com] On Behalf Of Philippe Jackson Sent: Wednesday, February 22, 2006 12:09 PM To: toasters@mathworks.com Subject: maxing out the filesystem
This is my first time posting Â... I just inherited 2 older filers. 840 and 960 models
Unfortunately they didnÂ't come with nearly enough disk space for our needs.
I know I canÂ't fill the volumes to 100% and expect them to work Â... but how
high can I fill the volumes and expect it to work and performance not to sufferÂ.... Can I go to 95% if I turn off snapshots?
Any feedback or experience from filers at 95% would be appreciated Â... IÂ'm hoping to learn from other peopleÂ's mistakes this time.
Of course thereÂ's always the option of buying more disk Â... but for now I need to see what I can do with what we've been given without spending more money.
Cheers Philip
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