Exam Associate Cloud Engineer topic 1 question 128 discussion

C is correct, local SSD has more IOPS

Correct Answer is (C): Performance Standard persistent disks are efficient and economical for handling sequential read/write operations, but they aren't optimized to handle high rates of random input/output operations per second (IOPS). If your apps require high rates of random IOPS, use SSD persistent disks. SSD persistent disks are designed for single-digit millisecond latencies. Observed latency is application specific. https://cloud.google.com/compute/docs/disks#performance

Correct A. A Local SSD is generally more expensive than a Zonal SSD Persistent Disk. And The ephemeral nature of Local SSDs can lead to additional costs for data replication or backups. So C is a good option for high throughput, but in terms of achieving increased throughput for the least amount of cost, A is the better option.

C. Migrate to use a Local SSD on the instance. Local SSDs provide high-throughput, low-latency storage that is physically attached to the instance. This can be beneficial for applications experiencing excessive disk read throttling, especially when dealing with large files. Local SSDs are ideal for temporary data that can be recomputed or regenerated if lost, and they can offer improved performance compared to Zonal SSD Persistent Disks. (https://cloud.google.com/compute/docs/disks/local-ssd#create_local_ssd_instance) for detailed instructions.

Local SSD provides more throughput than Persistent disks and is cost effective solution. So, correct answer is C.

C. Migrate to use a Local SSD on the instance. Local SSDs provide higher throughput and lower latency compared to Zonal SSD Persistent Disks, and are optimized for use cases that require high-speed, temporary storage. They are physically attached to the instance, so network latencies are minimized. However, they are not intended for long-term storage and may not provide the same level of durability as persistent disks. Since the application is primarily reading large files from disk and experiencing disk read throttling, using a Local SSD should provide a significant improvement in performance while minimizing costs. Increasing the size of the Zonal SSD Persistent Disk or increasing the allocated CPU to the instance may provide some improvement, but are unlikely to fully address the disk read throttling issue. Migrating to a Regional SSD is also not likely to improve performance significantly, as the disk is still separate from the instance and network latencies can impact performance.

According to the page containing the tables and to the tables "https://cloud.google.com/compute/docs/disks/performance#n1_vms" and "https://cloud.google.com/compute/docs/disks/performance#n2_vms", the number of CPU cores greatly influence the available max. read THROUGHPUT ("excessive disk read throttling on its Zonal SSD Persistent Disk", "The application primarily reads large files from disk.") on general purpose VMs. The question also requires minimizing the costs, however, as Local SSDs are EPHEMERAL, they are out of question for the scenario at hand. So, answer "B" seems to be the correct one.

C. Migrate to use a Local SSD on the instance

C is the correct Answer, Local SSDs Local SSDs are physically attached to the server that hosts your VM instance. Local SSDs have higher throughput and lower latency than standard persistent disks or SSD persistent disks. The data that you store on a local SSD persists only until the instance is stopped or deleted. Each local SSD is 375 GB in size, but you can attach a maximum of 24 local SSD partitions for a total of 9 TB per instance. Performance Local SSDs are designed to offer very high IOPS and low latency. Unlike persistent disks, you must manage the striping on local SSDs yourself. Combine multiple local SSD partitions into a single logical volume to achieve the best local SSD performance per instance, or format local SSD partitions individually. Local SSD performance depends on which interface you select. Local SSDs are available through both SCSI and NVMe interfaces.

had this question today

C is correct Local SSDs are physically attached to the server that hosts your VM instance. Local SSDs have higher throughput and lower latency than standard persistent disks or SSD persistent disks. The performance gains from local SSDs require certain trade-offs in availability, durability, and flexibility. Because of these trade-offs, Local SSD storage isn’t automatically replicated and all data on the local SSD might be lost if the instance terminates for any reason. Ref: https://cloud.google.com/compute/docs/disks#localssds Ref: https://cloud.google.com/compute/docs/disks/performance#type_comparison

C can´t B for the reasons explained here in the answers (local disk info will be totally deleted if you restart or delete your vm). Then A or B. Google recommends to increase the size of the disk as performance of the disk is linear to the size of the same. But Im wondering if 1TB is too much (it is almost 2 times more the original size of the disk, and that sounds like too much, plus if with 350GB the files already fit there, then increasing the size of the disk "a little bit more" should have been a better approach to test how the performance increases. Then Google Also recommends to add more CPU to get a better IOPS, it might be cheaper than option A if the right machine with more CPU is chosen. Answer: B

Local SSD .. C is right

C is correct.

Go with C As Local SSDs have high IOPS

C for me. https://cloud.google.com/compute/docs/disks#performance

Correct Answer is B From both tables: https://cloud.google.com/compute/docs/disks/performance#performance_by_disk_size https://cloud.google.com/compute/docs/disks/performance#machine-type-disk-limits The general purpose vm limit is less than ssd persistent disk size limit of 250-500