Tag: cache
Cache file size of “Cache on device RAM with overflow on hard disk” is growing faster than “Cache on device hard disk”
- Cache Type = “Cache on device hard disk”
The block reservation of “Cache on device hard disk” is ONLY 4KB, and it’s random I/O.
- Cache Type = “Cache on device RAM with overflow on hard disk”
Since “overflow on hard disk” is vhdx format, the block reservation is 2MB & required for sequential I/O, which will provide better performance than legacy local write cache, but it will consume more filesystem usage.
Hence if there’s heavy IOPS occurred on target device, and RAM cache is running out of range, “overflow on hard disk” cache will be generated, which may grow very fast.
Related:
Error “No Apps available at this time” on workspace for iOS app after upgrading to ADC 13.0 build 52.24
Version 13.0 build 52.24 do not set pwcount cookie in response to /vpn/index.html request as below.
HTTP/1.1 200 OK
Date: Fri, 08 May 2020 05:19:10 GMT
Server: Apache
X-Frame-Options: SAMEORIGIN
Last-Modified: Fri, 08 May 2020 04:56:44 GMT
Accept-Ranges: bytes
Content-Length: 3674
Cache-Control: no-cache, no-store, must-revalidate
Pragma: no-cache
Expires: 0
Keep-Alive: timeout=15, max=92
Connection: Keep-Alive
Content-Type: text/html; charset=UTF-8
Set-Cookie: pwcount=0;Secure;HttpOnly;Path=/;expires=Wednesday, 09-Nov-1999 23:12:40 GMT
Cache-Control: no-cache
Related:
Is ADC impacted by CVE-2020-10110, CVE-2020-10111 and CVE-2020-10112
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-10110
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-10111
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-10112
No, ADC is not impacted by these CVEs
CVE-2020-10110
There is no sensitive information disclosure through the cache headers on Citrix ADC. The “Via” header lists cache protocols and recipients between the start and end points for a request or a response. The “Age” header provides the age of the cached response in seconds. Both headers are commonly used for proxy cache and the information is not sensitive.
https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Age
https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Via
CVE-2020-10111
Citrix ADC only caches HTTP/1.1 traffic for performance optimization. In conjunction with the response for CVE-2020-10112, the reported behavior is not considered a security issue.
CVE-2020-10112
By default, Citrix ADC only caches static content served under certain URL paths for Citrix Gateway usage. No dynamic content is served under these paths, which means those cached pages would not change based on parameter values. All other data traffic going through Citrix Gateway are NOT cached by default.
Related:
ShareFile Drive Mapper is slow to load
Drive Mapper is an API driven tool that only caches local data, and the files seen in the directory are often not actually housed on your local computer. Many users sometimes fail to understand that actions they perform will not be as responsive as in other areas of the File Explorer, seeing as how they are dependent on network activity. Frequent directory changes and working with larger/numerous files will affect how the program functions.
The application is fastest when you are navigating among common drives, the size of data which is less than the cache setting. When you exceed that setting, Drive Mapper has to dump data to make room for more data, and files or folders that you were using and accessing very quickly are now much slower, as the application has to re-download the associated files. Having an increased cache will help you keep more data on the machine and improves performance.
Regularly restarting the affected computer on at least a daily basis, and verifying the version of software installed is the most current, are recommended.
Related:
Symantec Endpoint Protection Manager database Slow Issue
Hi,
Recently we are having issue with SEPM portal slowness.
we have done root cause analysis and we have find that we have enought 16GB of memory on windows server but Symantec Embedad Database using only 550MB. As per symantec guide line we have access database and we have check that maxcachsize is configured as 512MB. we have check with following command select property(‘MaxCacheSize’);
But we are searching for the resolution that can upgrade the cache size.
Please help to resolve this issue.
Thanks
Shivang
Related:
How to Resolve Browser Related Issues When Using ShareFile
Your browser cache stores temporary information to speed up web browsing. Whenever you encounter a problem with the ShareFile web app, we highly recommend clearing your browser cache to eliminate any potential problems that may arise from cached versions of web pages, including stored settings.
ShareFile recommends clearing your cache when:
- Preview fails or is otherwise broken / generating an error
- Page fails to load
- Cannot access certain menu in settings section of your account
- Changes to account settings not taking effect immediately after adjusting them
- Other application discrepancies not mentioned in this article
Related:
The future of Caching feature from market view
based on the high speed of current conections over both wired and cellular conection and the existance of several regional CDN:
does customer/market still need the on premise caching feature?
is it a main key player feature for the appliance or it just an add-on?
Related:
Citrix ADC Integrated Caching Counters
This article contains information about the newnslog Integrated Caching counters and a brief description of the counters.
Using the Counters
Log on to the ADC using an SSH client, change to SHELL, navigate to the /var/nslog directory, and then use the ‘nsconmsg’ command to see comprehensive statistics using the different counters available. For the detailed procedure refer to Citrix Blog – NetScaler ‘Counters’ Grab-Bag!.
The newnslog Integrated Caching counters
The following table lists the different newnslog Integrated Caching counters and a brief description of the counter.
newnslog Counter |
Description |
cac_tot_req |
Total cache hits plus the total cache misses. |
cac_cur_pcb_hit |
This number should be close to the number of hits being served currently. |
cac_tot_non304_hit |
Total number of full (non-304) responses served from the cache. A 304 status code indicates that a response has not been modified since the last time it was served. |
cac_tot_304_hit |
Object not modified responses served from the cache. |
cache_tot_hits |
Responses served from the integrated cache. These responses match a policy with a CACHE action. |
cache_percent_304_hits |
304 responses as a percentage of all responses that the NetScaler appliance served. |
cache_percent_hits |
Cache hits as percentage of the total number of requests. |
cache_recent_percent_304_hits |
Recently recorded ratio of 304 hits to all hits expressed as percentage |
cache_recent_percent_hit |
Recently recorded cache hit ratio expressed as percentage. |
cac_cur_pcb_miss |
Responses fetched from the origin and served from the cache. Should approximate storable misses. Does not include non-storable misses. |
cache_tot_misses |
Intercepted HTTP requests requiring fetches from origin server. |
cache_tot_storable_misses |
Cache misses for which the fetched response is stored in the cache before serving it to the client. Storable misses conform to a built-in or user-defined caching policy that contains a CACHE action. |
cache_tot_non_storable_misses |
Cache misses for which the fetched response is not stored in the cache. These responses match policies with a NOCACHE action or are affected by Poll Every Time. |
cache_tot_revalidation_misses |
Responses that an intervening cache revalidated with the integrated cache before serving, as determined by a Cache-Control: Max-Age header configurable in the integrated cache. |
cache_tot_full_to_conditional_request |
Number of user-agent requests for a cached Poll Every Time (PET) response that were sent to the origin server as conditional requests. |
cache_percent_storable_miss |
Responses that were fetched from the origin, stored in the cache, and then served to the client, as a percentage of all cache misses. |
cache_recent_percent_storable_miss |
Recently recorded ratio of storable misses to all misses expressed as percentage. |
cache_percent_successful_reval |
Percentage of times stored content was successfully revalidated by a 304 (Object Not Modified) response rather than by a full response |
cache_recent_percent_successful |
Recently recorded percentage of times stored content was successfully revalidated by a 304 response rather than by a full response |
cache_tot_successful_revalidation |
Total number of times stored content was successfully revalidated by a 304 Not Modified response from the origin. |
cache_percent_byte_hit |
Bytes served from the cache divided by total bytes served to the client. If compression is On in the NetScaler, this ratio might not reflect the bytes served by the compression module. If the compression is Off, this ratio is the same as cachePercentOriginBandwidthSaved. |
cache_recent_percent_byte_hit |
Recently recorded cache byte hit ratio expressed as percentage. Here we define byte hit ratio as ((number of bytes served from the cache)/(total number of bytes served to the client)). This is the standard definition of Byte Hit Ratio. If the compression is turned ON in the NetScaler appliance, then this ratio does not mean much. This might under or overestimate the origin-to-cache bandwidth saving depending upon whether bytes served by CMP in NetScaler are more or less than compressed bytes served from the cache. If CMP is turned OFF in the NetScaler appliance, then this ratio is the same as cacheRecentPercentOriginBandwidthSaved. |
cactor_max32_res_so_far |
Size, in bytes, of largest response sent to client from the cache or the origin server. |
cache_tot_resp_bytes |
Total number of HTTP response bytes served by the NetScaler appliance from both the origin and the cache. |
cache_bytes_served |
Total number of bytes served from the Integrated Cache. |
cache_comp_bytes_served |
Number of compressed bytes served from the cache. |
cac_tot_parameterized_inval_req |
Requests matching a policy with an invalidation (INVAL) action and a content group that uses an invalidation selector or parameters. |
cac_tot_non_parameterized |
Requests that match an invalidation policy where the invalid Groups parameter is configured and expires one or more content groups. |
cac_tot_inval_nostore_miss |
Requests that match an invalidation policy and result in expiration of specific cached responses or entire content groups. |
cache_percent_origin_ |
Percentage of origin bandwidth saved, expressed as number of bytes served from the integrated cache divided by all bytes served. The assumption is that all compression is done in the NetScaler appliance. |
cache_recent_percent_origin |
Bytes served from cache divided by total bytes served to client. This ratio can be greater than 1 because of the assumption that all compression has been done in the NetScaler appliance. |
cactor_tot_expire_at_last_byte |
Instances of content expiring immediately after receiving the last body byte due to the Expire at Last Byte setting for the content group. |
cac_tot_enable_flashcache |
Number of requests to a content group with flash cache enabled that were cache misses. Flash cache distributes the response to all the clients in a queue. |
cac_tot_delayed_logging |
Number of requests to a content group with flash cache enabled that were cache hits. The flash cache setting queues requests that arrive simultaneously and distributes the response to all the clients in the queue. |
cac_tot_parameterized_non304_hit |
Parameterized requests resulting in a full response (not status code 304: Object Not Updated) served from the cache. |
cactor_tot_parameterized_req |
Total number of requests where the content group has hit and invalidation parameters or selectors. |
cac_tot_parameterized_304_hit |
Parameterized requests resulting in an object not modified (status code 304) response. |
cache_tot_parameterized_hits |
Parameterized requests resulting in either a 304 or non-304 hit. |
cache_percent_parameterized |
Percentage of parameterized 304 hits relative to all parameterized hits. |
cache_recent_percent_ |
Recently recorded ratio of parameterized 304 hits to all parameterized hits, expressed as a percentage |
cactor_tot_pet_with_nostore_reval |
Requests that triggered a search of a content group that has Poll Every Time (PET) enabled (always consult the origin server before serving cached data). |
cache_tot_pet_hits |
Number of times a cache hit was found during a search of a content group that has Poll Every Time enabled. |
cache_percent_pet_hits |
Percentage of cache hits in content groups that have Poll Every Time enabled, relative to all searches of content groups with Poll Every Time enabled. |
cache_max_mem |
Largest amount of memory the NetScaler appliance can dedicate to caching, up to 50% of available memory. A 0 value disables caching, but the caching module continues to run. |
cache64_max_mem |
Largest amount of memory the NetScaler appliance can dedicate to caching, up to 50% of the available memory. A 0 value disables caching, but the caching module continues to run. |
cache_max_mem_active |
Currently active value of maximum memory. |
cache_utilized_mem |
Amount of memory the integrated cache is currently using. |
cactor_cur_hash |
Responses currently in integrated cache. Includes responses fully downloaded, in the process of being downloaded, and expired or flushed but not yet removed. |
cache_cur_marker_cell |
Marker objects created when a response exceeds the maximum or minimum size for entries in its content group or has not yet received the minimum number of hits required for items in its content group. |
cactor_err_no_buf |
Total number of times the cache failed to allocate memory to store responses. |
Related:
Wide space in the Cache-control header, max-age Value.
This Space is seen even after the Cache content group is configured without any additional spaces:
Due to this, browsers mights detect the Cache TTL value to be Null value.