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77

I suggest that you make the adjustments they have requested. Then benchmark the performance to show them that it made no difference. You could even go so far to benchmark it with LESS memory and vCPU to make your point. Also, "We're paying you to support the software with actual solutions, not guesswork."


51

Providing you are confident you are within the given system specs they document. Then any claim they are making in regards to requiring more RAM or CPU they should be able to back up. As the experts in their system I hold people to account on this. Ask them specifics. What information provided on the system indicates more RAM is needed and how did you ...


16

The big thing is to be able to prove that you are using best practices for your system allocation, notably RAM and CPU reservations for your SQL server. All this being said the easiest thing is to make the adjustments requested, at least temporarily. If nothing else it tends to get vendors over feet dragging. I can't count the number of times I've needed ...


12

For this specific situation (where you have VMware and application developers or a third party who does not understand resource allocation), I use a week's worth of metrics obtained from vCenter Operations Manager (vCops - download a demo if needed) to pinpoint the real constraints, bottlenecks and sizing requirements of the application's VM(s). Sometimes, ...


12

Please use RAID 1+0 with your controller and drive setup. If you need more capacity, a nested RAID level like RAID 50/60 could work. You can get away with RAID 5 on a small number of enterprise SAS disks (8 drives or fewer) because the rebuild times aren't bad. However, 24 drives is a terrible mistake. (Oh, and disable the individual disk caching feature... ...


11

I know this is probably a hypothetical question... But the IT world really doesn't work that way. There are realistic constraints to consider, plus other things that can influence IOPS... 50GB and 100GB disks don't really exist anymore. Think more: 72, 146, 300, 450, 600, 900, 1200GB in enterprise disks and 500, 1000, 2000, 3000, 4000, 6000GB in ...


10

The key to the answer to your question is read-ahead. Once upon a time, I also happened to have that issue. IOW, for optimal sequential read performance all disks should be permanently involved into Input. When you use dd w/o directio (see man dd), write operation is not being performed immediately, but goes through OS cache, so it has more chances to ...


8

poige is exactly right about the write cache, but here are more details. dd with zeros and using write cache is not the right way to benchmark (unless you want to test the write cache of course, which is probably only useful for a file system, to see how much it syncs metadata, creates new files, etc.) (and likely dd is always the wrong type of benchmark, ...


8

I used to work in support - and part of what you're asking sounds highly rational (and probably is): but there are a few questions to ask yourself prior to just doing the "performance enhancement" they're requesting are you running at least at the vendor's stated minimum system requirements already? if you're at least at minimum sysreqs, are you already at ...


8

Either ask to escalate the ticket or ask for a different rep. Depending on which vendor it is escalation may help if you say that you feel that the current level of support doesn't adequately address the issue. If they will not escalate then asking for a different rep may help because that requires much less "justification" since all it needs is to not be ...


8

Yes. Starting with rsync version 3.1.0 the --info=progress2 argument will give you progress on the entire transfer, including speed of the entire transfer. You can see a little bit of detail on the rsync man page.


7

To answer your question directly - all other things being equal = no change whatsoever when GB changes. You don't measure IOPS with GB. You use the seek time and the latency. I could re-write it all here but these examples below do all that already and I would simply be repeating it: http://www.ryanfrantz.com/posts/calculating-disk-iops/ ...


7

One place where there is a direct relationship between disk size and IOPS is in the Amazon AWS Cloud and other "cloudy services". Two types of AWS services (Elastic Block Store and Relational Database Service ) provide higher IOPS for larger disk sizes. Note that this is an artificial restriction placed by Amazon on their services. There is no ...


6

Do NOT use a single RAID 5 array across 24 1TB disks! I don't much care what you prefer to limit the answers to, it's a bad idea and you should look at other options. The odds of a disk failing go up with each disk. So does the time it takes to rebuild. When a drive fails, and you replace it, it will use as much IO across all the disks as possible to ...


4

I'll throw in my two cents. We've been pretty successful with this approach -- much better outcomes and less frustration on everyone's part. It requires a lot more effort than the blame-game and blindly adding resources, but it also has better chances of finding the underlying problem. When we have serious issues with our on-premise apps that are backed ...


4

I should point out that IOPS are not a great measurement of speed on sequential writes, but lets just go with it. I suspect the seek and write times of disk heads is pretty consistent despite the size of the disks. 20 years ago we we're all using 60GB disks with (roughly - certainly not linearly) the same read/write speeds. I am making an educated guess ...


4

You may want to test... But in general, hardware RAID controllers that can manage multiple volumes (logical drives, VD's, etc.) are handy in that they will allow the best use of the spindle count available to you. There's also a benefit to reliability. In short, I'd create an array of all disks and create appropriately-sized volumes within that.


3

No. There is not. This is why collector sets exist, as you've discovered.


3

The performance added to the storage scales with each spindle added. The rotational speed of the drive is the biggest factor, so adding a 10k RPM drive will give more performance (in terms of IO/s in random IO or MB/s in streaming IO) than a 7.2k RPM drive. The size of the drive has virtually no effect. People say small drives go faster simply because you ...


3

sudo persists as long as the process is running, so the solution is to use the setuid and setgid stanzas of upstart. The problem with that is that the line that sends the PID of the daemon needs root privileges. Here is a workaround: [name].conf: start on runlevel [2345] stop on runlevel [016] env HOME=/home/deploy env NODE_ENV=production setuid deploy ...


3

The real question is, who is in charge here? If you can't realistically switch to an alternative vendor, then they have the power, and all you can really do is go along with whatever they say and hope it will work out. Not a happy situation! Otherwise, I suggest you ask for another rep (as others have said), but make it clear you are not happy with the ...


3

First byte time typically represents the time it takes for the request to arrive, to be processed by whatever application is handling it, a response to be formulated and then sent back. Basically, the lions share of the amount of time it takes. The lastbyte time - first byte time in general is giving you a measure of throughput, the send request time - the ...


2

First off, you can use the great info here: http://penetrateit.wordpress.com/2012/02/11/exchange-2010-balancing-the-number-of-mailboxes-and-average-size-across-all-databases/ to figure out some stats needed to help balance the mailboxes across databases. Or you can use Steve's script here: http://www.stevieg.org/2010/09/balancing-exchange-databases/ ...


2

I'm going to post a view from the vendor's side. We had this customer that had this recurrent problem where the performance of the software would drop off every few hours or so to some truly abysmal rate then come back a few hours later. The bulitin profiler in the system indicated the system CPU (or possibly memory) speed was disgustingly slow, something ...


2

In case it's helpful to anyone coming across this post, as of Apache 2.4 (which wasn't released when this question was originally asked), the documentation no longer has the experimental warning regarding BufferedLogs. Now it only warns that a server crash may cause loss of log data [i.e. any log entries which haven't been written to disk yet because they ...


2

You could also use a Powershell script that deletes profiles of user's that haven't logged into a workstation in a certain length of time, say 30 or 90+ days, etc. Essentially, you want to use something like #Get user names that have logged onto workstation $Users = gwmi win32_networkloginprofile | where {$_.name -match "DomainName\\"} | where {$_.name ...


1

If you assume all else is equal, performance characteristics of disks of larger capacity don't change very much. An 10K RPM FC drive has very similar characteristics regardless of whether it's 300GB or 3TB. The platters rotate at the same rate, and the heads seek at the same speed. Sustained throughput likewise - not much difference. This is the root of a ...



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