In a Korean VPS environment, storage I/O impacts the operational efficiency of databases, websites, and high-concurrency applications. As business data grows, disk I/O latency and file system scheduling will vary. Storage I/O requires proper optimization to avoid slow responses, reduced throughput, and even downtime. Optimizing storage IP addresses and file scheduling strategies in a Korean VPS is key to ensuring system stability and performance. The following details various aspects, including identifying storage I/O performance bottlenecks, kernel-level optimization, file system selection, and scheduling strategy adjustments, along with practical steps using command lines.

Before optimizing storage I/O, you must accurately identify bottlenecks. Linux provides a variety of monitoring tools, such as iostat, iotop, and dstat.

Use iostat to view the overall CPU and disk I/O status:

iostat -x 1 10

This command outputs disk I/O usage in one-second intervals, focusing on the %util and await values. If %util is close to 100%, the disk is under heavy load; if await is high, I/O latency is severe.

Use iotop to view the I/O consumption of a specific process in real time:

iotop -o

Using tools like these, administrators can quickly identify whether a specific application or database process is causing I/O pressure, allowing targeted optimization.

After identifying the bottleneck, address file system parameters and kernel scheduling policies. Common file systems such as ext4, XFS, and Btrfs each have their own strengths in a VPS environment. Ext4 offers high stability and simple configuration, making it suitable for general business scenarios; XFS excels at high-concurrency large file writes; Btrfs provides snapshots and checksums, but requires more tuning for performance optimization.

For the ext4 file system, I/O performance can be improved by adjusting mount parameters. For example, add the following options to the partition in the /etc/fstab file:

/dev/vda1 /data ext4 defaults,noatime,nodiratime,barrier=0 0 1

noatime and nodiratime disable access time updates, reducing disk write overhead. barrier=0 disables the write barrier, improving write speed, but this requires reliable hardware. After the modification, you need to remount the disk:

mount -o remount /data

The XFS file system also supports parameter optimization. For example:

/dev/vdb1 /data xfs defaults,noatime,nodiratime,logbufs=8,logbsize=256k 0 0

The logbufs and logbsize parameters can increase the size and number of log buffers, making them suitable for high-IO scenarios.

In addition to the file system, the I/O scheduling policy is another key factor. The Linux kernel supports multiple scheduling algorithms, such as CFQ, Deadline, and NOOP. The scheduling policy determines how the kernel handles read and write requests.

To view the current scheduling policy used by the disk, run:

cat /sys/block/vda/queue/scheduler

The output may be:

noop deadline [cfq]

The "cfq" in square brackets indicates the currently used policy.

CFQ (Completely Fair Queuing) is suitable for mixed multi-process workloads, but may not perform well in high-IO applications. Deadline prioritizes read requests by setting an expiration time for requests, making it suitable for database applications. NOOP is the simplest scheduling method, handing requests directly to the hardware. It is suitable for use with SSDs in virtualized environments.

If you are running a database or high-concurrency application on a Korean VPS, it is generally recommended to choose Deadline or NOOP. To switch the scheduling policy, use:

echo deadline > /sys/block/vda/queue/scheduler

To permanently enable this setting, add the following to the grub configuration file:

GRUB_CMDLINE_LINUX_DEFAULT="elevator=deadline"

After changing this setting, execute:

update-grub && reboot

In addition to scheduling policies, you can also optimize I/O by adjusting kernel parameters. Edit the /etc/sysctl.conf file and add the following:

vm.dirty_ratio=10
vm.dirty_background_ratio=5
vm.swappiness=10

Then apply the settings:

sysctl -p

The dirty_ratio and dirty_background_ratio determine when dirty pages are written back to disk. Proper settings can help balance performance and stability.

For database workloads, you can also enable direct disk write mode. For example, enabling innodb_flush_method=O_DIRECT in the MySQL configuration file can reduce the overhead of double caching.

In a Korean VPS environment, caching can also be used to alleviate I/O pressure. By installing bcache or using ZFS caching, SSDs can be used as a cache layer for HDDs, improving overall performance. If you have a pure SSD VPS, you can improve concurrency by adjusting the queue depth:

echo 128 > /sys/block/vda/queue/nr_requests

This will increase the number of requests submitted at a time, improving throughput.

Finally, I/O optimization relies not only on the kernel and file system but also requires coordination with business logic. Regularly cleaning logs, archiving historical data, and enabling application-level caches (such as Redis and Memcached) can all reduce disk pressure. In multi-user or multi-process scenarios, proper disk quota management is also crucial to prevent a single user from completely occupying the disk space.

In summary, optimizing I/O for Korean VPS storage requires a multi-faceted approach: first, identify bottlenecks using tools, then select an appropriate file system and adjust mount parameters, and finally, choose an appropriate scheduling policy based on the business scenario. Furthermore, adjusting kernel parameters, application-level caches, and queue depths can further improve performance. For high-concurrency and database-related businesses, it is recommended to use the deadline or NOOP scheduling policy and disable unnecessary write operations when mounting the file system. By combining these strategies, the storage IO performance of the Korean VPS can be significantly improved, ensuring that the system continues to run stably under high load.