High frequency read on VMtools image might harm SD boot media

ESXi system disks do not require a lot of storage space on their boot media. That’s the reason why many installations use small and less expensive flash media instead of disks (and SCSI controller). It can be USB flash media for example or a SD-card.

The quality and reliability of these media varies. Even from batch to batch of the same type and the same vendor. Heavy write activity, but also heavy reading may significantly shorten the lifespan of flash media. In recent times we had to witness media that failed after less than a year in service. As long as the host keeps running this isn’t a bigger problem, because all crucial components are kept in ESXi host RAM. With VMtools-Image the situation is different. Each time a VM requests access to the image it will be read from flash. Especially VDI environments have a high read rate onto VMtools-Image, which may ‘burn’ the media.

VMware is aware of the problem and has introduced a migitation of the issue starting with ESXi 6.0 U3. It is not active by default and has to be activated manually. The migitation is fairly simple. During host boot VMtools-Image will be mapped into RAMDisk. Read access will be served from RAM and the lifetime of the media will be extended.

I will show here how to activate the option with web-client, PowerCLI or ESXi shell.

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Book Giveaway vSAN 6.7 Deep Dive

Within the next four weeks in March and April 2019 VMware will give away multiple copies of vSAN 6.7 Deep Dive by Cormac Hogan and Duncan Epping as eBook or signed paperback.


Unfortunately the eBook giveaway is for US residents only, because it’s only available via US Kindle Store. Just fill in the Google-Form and tell them why you’re a vSAN Fan. They will give away 300 eBooks.

Signed paperback

To win a signed paperback you need to follow VMware vSAN on Twitter. Once a week thee will be random happy hours. During happy hours you need to tweet with hashtag #vSANFan to enter the drawing.

From Zero to 132

When I applied for Top vBlog elections in November 2018 it was more or less a joke. Yesterday the final results of the Top 25 vBlogs have been streamed live. A recording can be found on YouTube. Amongst the Top 25 there are some of my personal favorites like
Vladan Seget (#2), William Lam (#1), Cormac Hogan (#3) and Melissa Palmer (#6). Congratulations!

Today all the remaining results have been published and I am really (!) surprised, that ElasticSky.de made it from zero to rank #132 of the general category.

Besides the votes there were election criteria like number of posts in 2017 and Google pageload index. Here my blog optimization paid off and I’ve achieved 95% in speed index. With some simple efforts I was able to significantly reduce pageload time.

Other categories

Besides the overall placement there are special categories. I’ve ranked #22 in “Favorite Independent Blogger” and #6 in “Favorite Non-English Blog”. In 2017 I’ve begun to publish in English too.

Thanks and outlook

Thank you so much for voting for my blog. It’s an encouragement to keep putting a lot of work into my blog. I’ll try to keep up the quality, although it’s not easy among everyday business. I’ve got a lot of topics to write about, but there are only 24 hours in a day. I’m not a professional blogger, I’m a consultant who spends most of the time at customer sites. Nevertheless I enjoy writing about IT subjects and surprises like these push me forward and motivate me to go on with blogging.

Thank you very much !