Azure区域-网站上的性能差异

Question

2 identical websites in Azure, they have identical setup. Both are running in Standard mode with instance size Small. There are no auto-scaling.

One website is running in region North Europe, the other in West Europe.

I experience about 25% difference in performance on websites. West Europe being the "slow one".

• Anyone have any information on this?
• Hands on experience with difference in performance from region to region?
• Someone with same setups that could try the same test?

Bellow is the simple stress test I ran to check performance.

    public ActionResult StressTest(int loopCount, int dbLoopCount)
    {
        var sw = new System.Diagnostics.Stopwatch();
        sw.Start();
        if (user.IsAdmin)
        {
            var hashTable = new Hashtable();
            var list = new List<int>();
            var random = new Random();
            for (var x = 0; x <= loopCount; x++)
            {
                list.Add(x);
                for (var i = 0; i <= loopCount; i++)
                {
                    hashTable[i] = list.Where(d => d == random.Next(0, x)).Count(); ;
                    hashTable[i] = list.Where(d => d == random.Next(0, x)).Count(); ;
                    hashTable[i] = list.Where(d => d == random.Next(0, x)).Count(); ;
                    hashTable[i] = list.Where(d => d == random.Next(0, x)).Count(); ;
                    hashTable.Remove(i);
                }
            }
        }
        sw.Stop();
        var loopTime = sw.ElapsedMilliseconds;
        sw.Restart();
        #region DBLoop
        .........
        #endregion
        sw.Stop();
        var dbTime = sw.ElapsedMilliseconds;
        return Json(new
        {
            WS = new
            {
                Loops = loopCount.ToString("N0"),
                Seconds = (loopTime / 1000.0),
                Milliseconds = loopTime
            },
            DB = new
            {
                Loops = dbLoopCount.ToString("N0"),
                Seconds = (dbTime / 1000.0),
                Milliseconds = dbTime
            }
        }, JsonRequestBehavior.AllowGet);
    }

The data base servers are VM's with Linux and MongoDB. The VM's in West Europe are about 35% slower than North Europe counterpart. Due to different Linux distribution, partitioning and replica setup, the test are not as valid as the website tests. It's hard to explain a 35% reduction in DB performance by any of the setup factors. It's tempting to think that 25% of that speed reduction are the same reduction I see on websites.

I have removed the DB stress test code, it's just consists of simple reads/counts. For the record: I have created 2 different websites in West Europe, and the slower performance is consistent. Also over several days, I first tested this on Tuesday, same results today.

Answer 1

Welcome to public cloud! Noisy neighbours, resource constrictions, transient faults and unexpcted hardware failure!

While all services (Azure and others) offer SLAs on availability most don't offer minimum performance thresholds for services unless this is being specifically sold as a premium benefit (such as Azure Premium Storage which offers guaranteed minimum disk IOPS). The provider will guarantee availability based on you meeting basic design concepts, but rarely offer guaranteed performance.

You could try redeploying the solution in the DC that is appearing to be slow. This may mean you are deployed to another host in the DC and avoid either a noisy neighbour or a host that is having problems. If you find a redeployment doesn't resolve your problem you might want to open a support ticket about the issue.

Answer 2

I feel less alone... I experienced the same thing jca. Big difference, my insert speed is about 2x faster in North Europe.

I guess it is "normal".