[EN] 77% of Organizations Experienced I/O Problems Since Virtualizing
Data collected from more than 2,654 IT professionals in North America and Europe reveals poignant information on how enterprises have struggled with I/O bottlenecks since virtualizing; what actions they have already taken since virtualizing and how they plan to improve I/O performance in the coming year.
As much as virtualization has provided cost-savings and improved efficiency at the server-level, those cost savings are typically traded-off for backend storage infrastructure upgrades to handle the new IOPS requirements from virtualized workloads due to I/O characteristics that are much smaller, more fractured, and more random than they need to be. This is due to the added complexity that virtualization introduces to the data path via the “I/O blender” effect that randomizes I/O from disparate VMs. The result is small, fractured I/O that reduces throughput and inflates IOPS by 50% on heavy workloads. Since native virtualization out-of-the-box does nothing to optimize the I/O stream, organizations must respond with either a brute-force approach of overbuying and overprovisioning with more flash hardware than necessary, or turn to 3rd party software solutions.
Key findings in the survey include:
77% of organizations report I/O performance issues since virtualizing
Nearly 1/3rd of respondents (28%) are so limited by I/O bottlenecks that they have reached an 'I/O ceiling' and are unable to scale their virtualized infrastructure
To improve I/O performance since virtualizing, 51% purchased a new SAN, 8% purchased PCIe flash cards, 17% purchased server-side SSDs, 27% purchased storage-side SSDs, 16% purchased more SAS spindles, 6% purchased a hyper-converged appliance
In the coming year, to remediate I/O bottlenecks, 25% plan to purchase a new SAN, 8% plan to purchase a hyper-converged appliance, 10% will purchase SAS spindles, 16% will purchases server-side SSDs, 8% will purchase PCIe flash cards, 27% will purchase storage-side SSDs, 35% will purchase nothing in the coming year
Over 1,000 applications were named when asked to identify the top two most challenging applications to support from a systems performance standpoint. Everything in the top 10 was an application running on top of a database
More than 70% of the responding IT professionals had virtualized more than 50% of their environment. Respondents from companies with employee sizes under 100 employees were excluded from the results, so results would not be skewed by the low end of the SMB market.
"It is clear that the unintended consequence of virtualization has been a tsunami of random I/O that has choked underlying storage subsystems, leaving organizations in a game of catch-up with no other choice but to spend their way out of the problem," said Brian Morin, SVP, global marketing, Condusiv.
Pessoalmente, vejo esses problemas ocorrerem na prática. Alguns sistemas de virtualização não gerenciam muito bem a isolação entre os diversos recursos e os clientes consumidores desses recursos. Já tive problemas bem desagradáveis com o Parallels/Virtuozzo e o MySQL, por exemplo. Pouca RAM pode fazer uma máquina virtual nessa plataforma literalmente se transformar num pesadelo, fazendo o sistema ir para a memória virtual, piorando mais ainda a situação do acesso à base de dados. Em um caso prático, nem reduzir o consumo de RAM para 512MB (em um VPS com 2GB) resolveu o problema. Migrar para uma solução virtualizada deve ser uma decisão planejada com atenção em muitos casos, especialmente se o acesso a disco for um requisito importante.