با عرض سلام و ادب
میخواستم یک تجربه جدید که مربوط به سرویس Multipath میشه رو با دوستان در میان بگذارم.
اگر تعداد دیسک‌های present شده به سیستم عامل از یک تعداد بیشتر باشه (البته با توجه به تعداد دیسک * تعداد path برای هر دیسک) باید در کانفیگ فایل multipath در قسمت default گزینه دیگری به نام
defaults {
max_fds <VALUE>
}
اضافه کنید. این کار را باید وقتی انجام دهیم که پیغامی مبنی بر
multipathd: error creating pipe for callout: Too many open files
در لاگ نمایان بشه.
توضیحات بیشتر را در زیر می‌توانید بخوانید:
Multipathd requires open file descriptors for each managed path. In the startup script for multipathd (/etc/init.d/multipathd), the maximum number of open file descriptors is increased from the system default of 1024 to 4096. However, in environments with large numbers of LUNs and/or paths to those LUNs, this value may be insufficient.
As a general rule of thumb, there should be two available file descriptors per path. For example, if 1000 LUNs were available through 4 paths each, multipathd would need 8000 open file descriptors (#LUNs x #paths x 2).
To increase the maximum number of file descriptors, the following entry must be place in /etc/multipath.conf:
Note - It is very common for no /etc/multipath.conf file to exist. In this case, create the file using only the configuration option listed above. Otherwise, add the max_fds setting to the 'defaults' section of the existing multipath.conf file. If the server is booting from the SAN, run `mkinitrd` to ensure the new multipath.conf is added to the initrd.
After modifying (or creating) the /etc/multipath.conf file, restart multipathd to cause the setting to take effect.
As a general rule of thumb, there should be two available file descriptors per path. For example, if 1000 LUNs were available through 4 paths each, multipathd would need 8000 open file descriptors (#LUNs x #paths x 2).
To increase the maximum number of file descriptors, the following entry must be place in /etc/multipath.conf:
defaults {
max_fds <VALUE>
}
Note - It is very common for no /etc/multipath.conf file to exist. In this case, create the file using only the configuration option listed above. Otherwise, add the max_fds setting to the 'defaults' section of the existing multipath.conf file. If the server is booting from the SAN, run `mkinitrd` to ensure the new multipath.conf is added to the initrd.
After modifying (or creating) the /etc/multipath.conf file, restart multipathd to cause the setting to take effect.
Additional Information
Novell has tested multipathd with 16,000 available LUN/path combinations. As long as the system has enough resources to support the required open files, and the max_fds is set appropriately, large numbers of LUNs and/or paths should work properly.
منبع:
https://www.novell.com/support/kb/doc.php?id=7008051